Displaying blue photos on the forum

[Michael G]

One of the problems that seems to reoccur on the forum is getting scraping photos to display the blue properly. I wondered the other day whether coloured filters might help - either blue to knock down the background or another colour to give a better contrast (make the blue darker).
We have a few photographers around - any thoughts?
(I'd try it out but don't want to buy filters if it will not work)

Michael

[BobL]

One of the problems that seems to reoccur on the forum is getting scraping photos to display the blue properly. I wondered the other day whether coloured filters might help - either blue to knock down the background or another colour to give a better contrast (make the blue darker).
We have a few photographers around - any thoughts?
(I'd try it out but don't want to buy filters if it will not work)
Michael

Blue is a tough colour for digital camera sensors to capture and display accurately.
The sensors are usually much more sensitive to the red end of the spectrum than the blue end.
You might be more successful by playing around with lighting than filters - have you tried photographing in daylight?

[FenceFurniture]

+1 for daylight Michael - hard to beat for realism and detail. It will depend on the subject as to whether overcast or strong sunlight is best If you are trying to show bare metal then overcast is probably more suitable, but for a blued surface sunlight may be the best.

Maybe you could post a pic that's giving you trouble?

[ian]

maybe there's no need to buy blue filters
my camera has a set of blue, red and green filters built in - you select them by menu options.

unfortunately I don't have access to bluing or a scraping sample, but perhaps black and white is an option

[Ueee]

Hi Michael,
I have had the same problem, i found for actually scraping that a cool white light helps the blue to be visible to the naked eye.
The best shot of a blued surface was in darker lighting, near one of the walls of the shed. I'll be sure to look at my camera settings next time i take a pic of any spotting.

Ew

[Metmachmad]

Judging by this subject name, "Displaying blue photos on the forum (http://www.woodworkforums.com/f65/displaying-blue-photos-forum-177627/)", I got excited and anticipated that I had found a seedier side to this forum, but alas, it has nothing to do with nakedness.

[.RC.]

Judging by this subject name, "Displaying blue photos on the forum (http://www.woodworkforums.com/f65/displaying-blue-photos-forum-177627/)", I got excited and anticipated that I had found a seedier side to this forum, but alas, it has nothing to do with nakedness.

You mean blue photo's like this topless one here -->> click here (http://www.practicalmachinist.com/vb/attachments/f10/18142d1261160854-just-comparison-cw.jpg)

[simonl]

Hi Michael,

another option maybe to use a polarising filter in sunlight. It may help reduce the reflected light from the metal and allow the blue to show up more or help reduce the contrast. Not sure whether a linear or circular polariser would work best though....

Just a thought..

Simon

[scottyd]

The problem may not be the camera at all, but the light youre using to illuminate the subject. Fluoro lights have pretty poor ranges of light, its one of the reasons theyre quite hard on the eyes. Someone mentioned sunlight, which is much better for light ranges.

Rather than changing bulbs for another type or colour, you could try shooting your photos in a raw format and adjusting the colour values in a good photography program like lightroom or photoshop. But then again, it requires a bit of learning and mucking around. Probably easier to just open the curtains.

[Anorak Bob]

Michael,

I deleted my earlier post because after reading the other replies, it was obvious I was missing the point. As Fence suggests, a photo illustrating your problem might help. Might also help me with my ability to comprehend.:no:

Bob.

[Michael G]

A photo illustrating your problem might help.

I had thought of that but then realised a photo of something I can't photograph well may not help...

The issue I (and a number of others) have is that a photo of a (blue) spotted surface on a silver scraped surface does not show up well - The naked eye can usually pick up the blue but a camera seems to flatten it right out. Your pics were better Bob, but then they were continuous blue.

Attached is a photo from one of Richard's posts in the scraping projects thread -
289112

The blue is just discernible but something to make it stand out more in the photo (I think) would be good. As an added bonus, it could start a whole new range of eye wear. I already have a set of cheap eye glasses in the shed I refer to as my welding glasses (they are slightly more powerful than than my reading glasses for a bit of bonus magnification) - with the right filtering perhaps we can also have some scraping glasses for enhanced blue perception.

Michael

[FenceFurniture]

That particular pic appears to be taken on a phone camera with a very high ISO rating (sensitivity rating) hence the grain or "noise". Without wishing to pick on that photo, phone cameras don't often yield the desired result when it comes to detail.

It looks like there is a spot of sunlight coming through which may have fooled the light meter into an overall darker exposure.

[.RC.]

The blue is just discernible but something to make it stand out more in the photo (I think) would be good.

Yes the silver background washes out the blue...

I know nothing about cameras, but I think it is to do with the contrast ability of the camera...

Some newer cameras have the ability of High Dynamic Range... This may be the answer...

High-dynamic-range imaging - Wikipedia, the free encyclopedia
(http://en.wikipedia.org/wiki/High-dynamic-range_imaging)
Here is a an example from the above link that actually look sfake, due to it's vibrance..

File:HDR image + 3 source pictures (Cerro Tronador, Argentina).jpg - Wikipedia, the free encyclopedia (http://en.wikipedia.org/wiki/File:HDR_image_%2B_3_source_pictures_%28Cerro_Tronador,_Argentina%29.jpg)

[A Duke]

You mean blue photo's like this topless one here -->> click here (http://www.practicalmachinist.com/vb/attachments/f10/18142d1261160854-just-comparison-cw.jpg)Nice box.

[FenceFurniture]

Yes, cameras don't see contrast the way we do. A red or yellow filter should darken up the blue parts. A polariser would not be my first choice, but would possibly be worth experimenting with. Even using tungsten light with the camera still set to daylight may show a benefit (in essence it would be a yellowish filter). Another option might be to put a yellow or red party light in a tungsten lamp, and again keep the camera set to daylight.

Metal always represents the biggest challenge in takng a well lit pic: if it's shiny/polished it will reflect whatever it sees, so point source light (i.e. on-camera flash) is useless as it results in a hot spot surrounded by darkness.

Brushed metal is easier as it can be placed on a white or pale grey backdrop and will usually pick up that, even if the face is at 90° to the backdrop (depending upon how satin finish the brushing is).

Sometimes you even have to go to the lengths of using angles of incidence/reflection: point the camera at the face of the metal at (say) 45° and have a white reflector at the other 45° angle, and the reflector itself may have to be lit so that it brings enough light back to the metal to be bounced back into the camera. That's why light tents work with metal pen parts - the metal can only reflect white because that's all it can see, even with a curved metal surface.

[Stustoys]

Would messing with the white balance help?
I mean something like setting the white balcance on a piese of "light red" paper?

(is this a rough way of doing what scottyd is talking about?)

I must say I've never even tried the different light type settings built into the camera. Time for some testing, great day for photos here.

Stuart

[nadroj]

Would a photo editor like the free GIMP be any good?

Jordan

[FenceFurniture]

Would messing with the white balance help?
I mean something like setting the white balcance on a piese of "light red" paper?

(is this a rough way of doing what scottyd is talking about?)Not really Stuart - he's talking about manipulating the image after the event. Always best to start with the best data possible and then manipulate any adjustments required.


I must say I've never even tried the different light type settings built into the camera. Time for some testing, great day for photos here.

StuartYep, there are some really useful settings in there. My shed has warm LED globes in it, along with a few halogen task lamps. For example, I always get a much better result using the Tungsten setting on the camera, rather the Auto White Balance (still stays a bit too warm).

[FenceFurniture]

Just had a thought re polarising which may yield the best result of all: a lens-polariser has absolutely no effect on metal whatsoever. However, double polarising does. This means that you polarise the light source with a PL gel (available from professional camera shops) and then use a P filter on the lens (either Linear or Circular, depending on what is recommended for your cameras light meter). It eliminates all reflections completely, including metal.

Link to supplier in the USA (http://www.polarization.com/polarshop/) (but there will be some here).

Another USA link. (http://www.bhphotovideo.com/c/product/45130-REG/Rosco_101073001720_Polarizing_7300_Filter.html)

Have a look at page 12 of this (slow loading) pdf. (http://www.betterlight.com/downloads/conference10_speakers/guyer_Polarization.pdf) It shows the effect of cross polarising on alum foil.

[simonl]

Hi all,

well my curiosity got the better of me. I dug out an old circular polariser and my digital camera, then cleaned the (flight :U) rust of my square block from the hand scraping class and did a spot of spotting....

It was my intent to show a pic with and without the polariser in both sunlight and filtered light (in the shed). Unfortunately my results were completely unexpected. No difference! In fact I have not even bothered to post the pics because they look the same. Maybe a linear polariser may show better results, I dunno. I don't have a linear so I couldn't try it.

The only thing I can confirm (which everyone already knew anyway) is that you get better results with filtered sunlight or sunlight from overcast day than direct sunlight.

So, in short. Ignore my idea of a circular polariser! :B

Simon

[FenceFurniture]

...a lens-polariser has absolutely no effect on metal whatsoever. However, double polarising does. To be expected Simon.

[scottyd]

Would messing with the white balance help?
I mean something like setting the white balcance on a piese of "light red" paper?

(is this a rough way of doing what scottyd is talking about?)

Yep, pretty much. Shooting raw gives you more range to play with in terms of correcting white balence. You could also do (in photoshop) an increase of contrast on the blue channel only, which would stop the rest of the picture from looking crap.

There are plenty of ways to manipulate the data in an image, but its only possible to manipulate data if you capture it first. If there isnt any blue light to be collected by the camera, then there will be no blue light in the image. If youre shooting in such a dark place (as someone else pointed out with the high iso comment), then you might not have the blues there to play with.

[Stustoys]

I have a light box with 6x30W tubes in it I could try. But that would be just about the worse light source for this sort of thing right? (or will this make things worse anyway?)

I had found that using max zoom helped*......though that would also increase the ISO right?

Lots of my scrapping is done at night(though DLS will help that for the minute) so while sun light might be nice, its not always possible. When I remember I like to take a picture each cycle with roughly the same setup, as it lets me flip through them to see how things are coming along. I doubt its really necessary for the pros.

Stuart

*didnt know why but I think its covered in the above pdf.

[Michael G]

Not really Stuart - he's talking about manipulating the image after the event. Always best to start with the best data possible and then manipulate any adjustments required.

Don't know where you got that idea from - in the first post I asked about filters. I don't want to get into lots of post picture manipulation. Whether by changing a camera setting or using some sort of filter, I just want a picture that can be displayed that will show spotting clearly, especially for finish work (that is, thin layers of blue).

Michael

[FenceFurniture]

I have a light box with 6x30W tubes in it I could try. But that would be just about the worse light source for this sort of thing right? (or will this make things worse anyway?) Sodium vapour would be worse......


I had found that using max zoom helped*......though that would also increase the ISO right?The ISO shouldn't change just by zooming (unless there's some fancy built in algorithm to increase ISO with zooming to assist with camera shake - never heard of it though).


Lots of my scrapping is done at night(though DLS will help that for the minute) so while sun light might be nice, its not always possible. When I remember I like to take a picture each cycle with roughly the same setup, as it lets me flip through them to see how things are coming along.That adds a new twist which can really only be solved by repeatable artificial light. Tungsten or LED will give the biggest part of the spectrum

[FenceFurniture]

Don't know where you got that idea from - in the first post I asked about filters. I don't want to get into lots of post picture manipulation. Whether by changing a camera setting or using some sort of filter, I just want a picture that can be displayed that will show spotting clearly, especially for finish work (that is, thin layers of blue).

MichaelApologies Michael, I was referring to nadroj's post - I should have been clearer. Agreed that post pic fooling around is to be avoided as much as possible. Just wish I still had a PL gel for a light to experiment with.

[cba_melbourne]

There are two issues to consider:

1)

Light in real life contains the whole spectrum of colors, ranging seamlessly from violet at one end to red at the other end, with blue green yellow and orange in between.

Photography is only a simplification of this reality. Photography only uses three colors (red, green and blue). By mixing these it tries to reproduce reality as good as possible. For example, photography can not faithfully reproduce a color like gold or silver. The former will look as a dull yellow, the latter as a dull grey.

This is the reason, why in printing often more than only three colors are used. If you look at shiny cardbord packaging boxes, you will often find an area under a lid where a strip of reference colors is printed. Besides the standard colors yellow, magenta, cyan and black you may see one or several additional colors are used, depending of the items shown in the picture. The use of a separate color "gold" or "silver" can be used to print realistic looking goldcoins or a silver trophy. The simplification of only using only a limited number of colors also has another effect. For example, two pieces of colored tissue may look exactly the same under daylight, buy may appear to be quite different colors under incandescent light. Something important to consider in the tinting business.

Back to the machine way scraping pic. If you wanted to represent this in an expensive color print book, you would add to the standard colors the special colors for steel and for "prussian blue" (which is the name of the blue color dye used in layout blue). But in photography you cannot add to the three colors RGB. You are stuck with the three color RGB and whatever can be mixed with these three colors.

2)

In a photography, you record the colors and intensities of light reflected from the surfaces of the objects in the picture. Sunlight contains equally all colors in the spectrum (a continuous spectrum), so does the light from halogen bulbs. But if you look at the light from fluorescent bulbs, it only contains a few very narrow lines at certain wavelengths, NOT a continuous spectrum. If almost no blue is present in such light, then you should not expect to see much blue reflected either. In an extreme case, where blue light is completely missing, blue surfaces will be shown as grey. An extreme example are the yellow Natrium vapor street lights, they emit almost monochromatic light. If you have such a yellow street lamp, do this experiment at night: take your kids box of color pencils under this street light, how many colors can you identify? The yellow pencil will look very bright yellow, all others will only appear as different shades of grey. You are effectlively color blind. Hence the rule: if you need to see proper colors, you should never use fluorescent or LED light. Choose Sunlight, or at least some bright form of incandescent light instead.

You can enhance the "blues" in your picture in several ways. You can use a lamp with a "higher color temperature". For example, a halogen bulb emits more blue color if operated at a higher voltage. The higher voltage results in a hotter filament, hence also the term higher color temperature. But there are bulbs that are made with a finer filament, to achieve the same effect at normal voltage. In general, lamps with a higher color temperature have a shorter life too. You could also put a blue filter in front of the lamps and achieve the same outcome. The blue filter lets blue pass but absorbs yellow.
Or you can manipulate the picture after it being taken, using a photo editing software that lets you apply a blue filter. Chris

[Oldneweng]

I have a light box with 6x30W tubes in it I could try. But that would be just about the worse light source for this sort of thing right? (or will this make things worse anyway?)

I had found that using max zoom helped*......though that would also increase the ISO right?

Lots of my scrapping is done at night(though DLS will help that for the minute) so while sun light might be nice, its not always possible. When I remember I like to take a picture each cycle with roughly the same setup, as it lets me flip through them to see how things are coming along. I doubt its really necessary for the pros.

Stuart

*didnt know why but I think its covered in the above pdf.

Most people tend to do most of their scrapping at night. I think it may have something to do with the consumption of alchohol that also happens more at night.

Dean

[Stustoys]

Its muscle relaxant Dean ;)


I believe photograhers used to run 240V bulbs at about double V. Sure they wouldnt last long but it was no big deal.
Anyone got an idea how far over volt you can run say a car 12V headlight?
Would they be better on AC or DC?
(I guess I could try a headlight as is first)

Stuart

[Michael G]

I went out and had a play with the camera settings, both white balance and "scenes" while taking photos without flash. One thing that is noticable is the unevenness of the lighting I have. On the right side of the photo the light is coming from a skylight. The fresh scraping adds an extra degree of difficulty picking up the blue. As a few have suggested, a diffuser is needed to give even light. None of them had a particularly noticeable affect in making the spotting stand out. The best was the "food" setting (below). The subject is a little 4"x10" Wing surface plate , ex DoD. I've circled a couple of places where some kind soul has used it as an anvil. For some reason it is crowned in the middle when I blue it against the cheeseboard (spring back after being thumped?). Why would you use a beautifully scraped surface like that?

289132

The other photo (below) is the same thing but manipulated in MS Office Picture Manager where I've turned both the amount and the hue right down in the colour settings. This is the sort of effect that I was hoping to get straight from the camera - the back ground is muted but the blue is bright. If I can find the instructions that came with the camera I may be able to define a custom setting that does that although it is a long shot.

289133

I guess the only way I'll get real time is with a set of those google glasses, a web cam and some costly software. At least for posting photos here there looks to be a way of bringing up the contrast.
This the photo of Richard's using the same treatment. Is it any better? Hard to say.
289148

Michael

[Ueee]

Here is a pic of mine, also manipulated in MS Offices picture manager. I adjust Saturation +50, Contrast +25 and Brightness -25. Easier to get it right with the camera though....

[cba_melbourne]

Anyone got an idea how far over volt you can run say a car 12V headlight?
Would they be better on AC or DC?
Stuart

As a rule of thumb for 12V halogen globes (car headlights or dichroic downlights or projector lamps) lowering the voltage by 0.5V below rated voltage can nearly double life. Just remember whilst ordinary downlights are rated at 12.0V, car headlights are actually rated at the higher battery charge voltage of 13.8V. Increasing the nominal voltage by 0.5V will about halve live.

As an example, a professional use Osram decostar downlight bulb I am holding in my hand is marked on its package with a life of 3100h at 12V and produces 2200cd, the same bulb is rated for a life of 5000h at 11.5V whilst producing 2050cd. The Osram website has lots of additional information on their data sheets - you would be surprised how many different bulbs there are that look exactly the same and fit in the same downlight (at last count almost 100, with different price, different life, different light output, different wattage, different beam angle, different reflector coating, different color temperature.............). Chris

Edit AC or DC makes no difference as long as the RMS power stays the same. With one exception, in a strong magnetic field the filament acts like a solenoid coil and vibrates with 50 or 60Hz causing it to break in few hours - that is why in MRI rooms they always use DC for lights.

[Anorak Bob]

I had a play around with my camera this afternoon and found that camera angle influenced the outcome maybe more than the light source. The lighter photo was taken with light entering an east facing door a meter and a half away from the blued block and no fluorescent light. The darker photos were under fluorescent light. The camera was on auto everything, standard "as delivered" settings except for ISO which I'd wound back to 400.

I may have been a touch generous with the blue.

BT

[Stustoys]

Hi Micheal,
When it seems to work pretty well(even if a little on the ugly side)

Hi cba,
Thanks for that I'll have a play when I get a minute.

Stuart

[Michael G]

Ugly - well maybe it is, but they say that "form follows function". (Industrial designer's saying (form being appearance) - usually only remembered when they can't get get something looking as they want it to.)

One question that I do have for the assembled scrapers among us - both in Richard's pic and Ewan's pic (I'm ignoring Bob's because as he says the blue may be too heavy) the blue is showing a whole bunch of short lines. I was under the impression that they should be broken up as the ideal surface consists of discrete spots. Have I mis-understood? (the photos probably have been taken mid job anyway) This view probably comes from surfaces being described as "X spots per square inch"

Michael
(high contrast photos causing comment already)

[simonl]

One question that I do have for the assembled scrapers among us - both in Richard's pic and Ewan's pic (I'm ignoring Bob's because as he says the blue may be too heavy) the blue is showing a whole bunch of short lines. I was under the impression that they should be broken up as the ideal surface consists of discrete spots. Have I mis-understood? (the photos probably have been taken mid job anyway) This view probably comes from surfaces being described as "X spots per square inch"

Michael


Hi Michael,

It's my understanding that the required spots/inch is dependent on the use of the surface. Difference surfaces require different minimum number of spots/inch. Some require 8 - 10 some 12 and some 25 spots/inch.

I'm guessing that the shape of the spots may have a little to do with the tool being used and/or maybe to a certain extent, the individual who is scrapping?
Long skinny spots could be caused if a person only ever scrapped in one direction which would cause small channels and show the blue up as long streaks. Not that I'm suggesting this has been done on these occasions.
Perhaps the physical size and dimensions may play a part too. Long skinny sections are going to be inherently difficult to scrape. It may also have to do with the blue being used, how much and whether it's been spotted on CI or granite plate. One surface can be made to look different under different conditions. Then again, none of these may have anything to do with the nature of the spotting in those pics. Interested in Stu's comment and maybe Phil (Machtool) if he's reading...

Bob's photo of the block from the scrapping class looks very similar to mine..... Or should I say that mine looks very similar to Bob's :q but one thing I did notice in the scrapping class, no two people scrape the same way.

Simon

[Anorak Bob]

Ok, I'll have another go with less blue :-.

I knew Stuart posted many a blued photo in his thread on cross slide scraping http://www.woodworkforums.com/f65/cross-slide-scraping-152680/index4.html#post1490478 so I looked and found this which I thought was a pretty good example of an evenly illuminated example of blued scraping. So Stu what was the technique you employed?

289220

[Stustoys]

Hi Guys, not a lot of time this morning.

One question that I do have for the assembled scrapers among us - both in Richard's pic and Ewan's pic (I'm ignoring Bob's because as he says the blue may be too heavy) the blue is showing a whole bunch of short lines. I was under the impression that they should be broken up as the ideal surface consists of discrete spots. Have I mis-understood? (the photos probably have been taken mid job anyway)
As I understand it, It doesnt matter until you have full bearing and are pretty much finished, then you start to be a little more fussy and split all those lines/big spots.


Interested in Stu's comment and maybe Phil (Machtool) if he's reading...
Think you might have that backwards ;)



I knew Stuart posted many a blued photo in his thread on cross slide scraping http://www.woodworkforums.com/f65/cross-slide-scraping-152680/index4.html#post1490478 so I looked and found this which I thought was a pretty good example of an evenly illuminated example of blued scraping. So Stu what was the technique you employed?
Now thats a bit of a problem, thats in the shaper, there is an 8" tube near by. I assume its a fluro? (though I'm not 100% on that, if I recall correctly there is only one terminal each end which I would have thought ruled out fluro, came with the house 23 years ago). Having said all that, I have some LED spot lights and a circle fluro on my magnifier that could have been in use....... so not a lot of help sorry.


Stuart

p.s. I should get some time this evening to have a play...though daylight will be a problem. Also BT I think most the "problems" might be from trying to get pictures on longer ways. That would make defuse light more important right?

[Abratool]

I had a play around with my camera this afternoon and found that camera angle influenced the outcome maybe more than the light source. The lighter photo was taken with light entering an east facing door a meter and a half away from the blued block and no fluorescent light. The darker photos were under fluorescent light. The camera was on auto everything, standard "as delivered" settings except for ISO which I'd wound back to 400.

I may have been a touch generous with the blue.

BT
Bob
I was reminded in seeing your beaut scraped cast iron piece of the good time we all had at the April 2012 Scraping School.
Learnt a lot & had a great time with a bunch of like minded blokes.
Good to see the blueing you have achieved on the block.
regards
Bruce

[Stustoys]

Well I had a play during the day and evening(as there are to many windows on my garage) and without boring you with 100 pictures I'll give you the short version.

Long shots with zoom seem to be the winner.

Outside is of course the winner though the angle the picture is taken from still has a lot to do with it.
The color of the background seems to make a difference(at least to my eyes, leaving the camera on auto).

Inside its all about how much light, its diffusion(?) and angle, followed by camera angle.
The type of light and camera settings for different light seem to make little difference.
I didnt try a different background.

Maybe if you were after the best possible picture and you had 1000W of halogen lights it would be an improvement but I only have about 50Wx2 bare bulbs(or 200X of LEDs, I had 20W I think).

So in answer to BT's question of my technique. It would seem blind luck was employed and I assume I kept taking pics from different angles until I had one that looked right.

Stuart

[.RC.]

Here is a picture of canode blue on some Turcite that I bought from Marko..

It is the saddle of Pinky..

I found I had to apply the canode heavier then I would have had I been spotting cast iron..

Something of a different colour would have been better... I tried yellow canode, but it turned green.... white would have been good I think..

[Anorak Bob]

Here is a picture of canode blue on some Turcite that I bought from Marko..

It is the saddle of Pinky..

I found I had to apply the canode heavier then I would have had I been spotting cast iron..

Something of a different colour would have been better... I tried yellow canode, but it turned green.... white would have been good I think..

It might be water under the bridge Richard as far as Pinky's saddle goes but a thread on Turcite and your of it would surely be interesting to me and a few others. Phil F exposed us to the stuff at the last scraping class, a follow up would be great.

Bob.

[Stustoys]

Shouldn't be hard to make in any color you can get grease in?
Would a clearish base work? Vaseline seems cheap enough, comes in a handle container and its good for the skin :p

I havent even tried yellow yet lol


Stuart

[Michael G]

It's the thinness of the spotting compound that seems to be the problem rather than the colour. The latest thought that I had was to find a pigment that had a UV trace in it (that is, something that fluoresce under UV light) and see if that helps. You would need to scrape under a UV light source though.

I think Vaseline has been tried as a carrier for pigment but did not work that well

Michael