Color Management

[Tom V]

To me, color management of digital files can be the most baffling part of digital photography. As far as I can tell, its results often cannot be directly seen or detected without careful comparison between two variations of the same image (ie: one image in sRGB and the same scene in AdobeRGB) under controlled conditions. I do understand that in order to get the most accurate color, or in other cases, the most appropriate color, images should be in a specific color space, depending on the output/results desired. I think that understanding color managment, and then being actually able to do something with that knowledge in regards to our digital images and manipulations, can result in the finest color possible.

The knowledge is within our grasp! Let us learn!

[cadams]

Tom, I agree completely regarding the baffling nature of color management. I'm a few months behind you on the learning curve, and hoping you've gotten it figured out :). I'm using a Mac and wondering how best to set it up for Raw file conversions. Converter EX offers three choices of color space: sRGB, Adobe RGB, and Fujifilm FinePix RGB 1.8 ICC profile. I have not seen the Fuji discussed....is it better for Mac? Or should I go with Adobe (2.2 gamma)?
Any ideas will be most welcome.


Chuck

[Tom V]

I have been converting my RAW files into the Fuji color space. I always use gamma of 1.8 (when I have a choice) on the Mac. I could never see a meaningful difference between the AdobeRGB and the Fuji FinePix RGB 1.8.

However, I may not be any further along the learning curve than I was several months ago.

I have never figured out my printing problems with my Epson 1270. After months of trying every combination of profile and paper. Last week I realized that my "high-end" LaCie Electron22blue (21" monitor) was not getting calibrated, despite my BlueEye hardware color calibrator. I called LaCie and they said to send it in. I sent it in, and a replacement is already in route.

My results look good in the magazines I submit my work to, so everything was working great even though my monitor was off a bit.

When I get the new monitor, I will attempt to make sure everything is calibrated and profiled correctly.

Never use sRGB color space unless you are trying to use the most limited gamut of colors out there.

[cadams]

Thanks for the conversion tips, I'm just preparing to convert my first test shots in Raw mode. Sorry to hear that your printer woes continue. I can't give much help there as I am currently using a HP Photosmart 1218. The rest of the world uses Epsons, and I suppose I will too eventually. But for my purposes, the HP does great. I suppose I may lose out on some color range now since it has only 4 colors of ink, but hey, there's always something else to buy right?

[cadams]

In the Photoshop Color Settings menu, after choosing color space, do you specify Color Management Policies?


-----------------
Chuck

[Tom V]

In Photoshop's Color Management Policies, I want to know what is going on, so I make it tell me whenever there is a mismatch between what is embedded and whatever my default is. I get files from customers that sometimes have embedded profiles, and I let them stay that way unless I am being relied on to fix the images. I like to get my images into AdobeRGB when i have a choice. Most of my work ends up printed on a printing press, so I usually end up converting everything to CMYK using SWOP standards.

[jknights]

The 'industry' standard (or as close as it gets) seems to be the Adobe 1998 RGB profile.

The reason that it is widely accepted is that the gamut is wider and also since most professional shops Mac or PC use Adope Photopshop or Illustrator which support this profile.
In addition the ability to move from Adobe 1998 to the full YMCK Linotype output is 'easier' never used it myself so I cant really comment.

Other common colour profiles sRGB use a reduced gamut so your colours do not have such a wide range of shades.


FYI According to Fuji, the FinePix RGB 1.8 ICC profile is recommended for use on Mac's as it suits their profile best. It however has a reduced gamut of 1.8.

I always use Adobe 1998.

[jknights]

Cut this info from the Fuji Hyperutility manual.

1. AdobeRGB (1998)
This was introduced as the working color space for Adobe Photoshop 5.0.
It incorporates colors that can be reproduced on almost all CMYK printers and is best suited to printing. This color space was introduced as “SMTPE-240E” in the RGB setting for Adobe Photoshop 5.0, and as “AdobeRGB (1998)” in the profile settings for version 6.0 onwards.

2. FinePixRGB 1.8
This color space applies a g value of 1.8 and is the standard color space used on Macintosh computers. FinePixRGB 1.8 uses the same colors as AdobeRGB (1998) and is best suited to DTP work on Macintosh computers.

3. sRGB (IEC61966-2.1)
The sRGB color space was formulated by the IEC and is the standard color space for monitors in Windows systems. This color space defines average characteristics for a wide range of different monitors and can be used as the standard color space in operating systems such as Windows.

The term “color space” refers to a range of 2-dimensional or 3-dimensional numbers that are used to express the colors that can be reproduced on a camera, display monitor or printer. Figure shows an xy chromaticity diagram for the sRGB and AdobeRGB color spaces. (An xy chromaticity diagram uses coordinates to represent color tones in 2 dimensions (brightness is excluded).)
The triangular areas on the xy chromaticity diagram indicate the colors that can be represented by the color space.
The further out a color appears on the xy chromaticity diagram, the brighter the color. This method for expressing colors is capable of showing all existing colors.


If you are really into color spaces see here:
http://www.aim-dtp.net

[cadams]

I am occasionally asked to shoot finish samples for furniture manufacturers. Color matching of this sort can be tedious and frustrating. As a practical matter, what I need to know is how best to set up my color management controls to ensure the most faithful reproductions all the way through to the commercial printer's output. To this end, is there any consensus? Does wider gamut give Adobe RGB an edge over FinePixRGB? Also, if the commercial printer is using Windows based PC's, does FinePixRGB present problems for him?

Thanks to all for your comments, links and opinions.

jknights: are you Macintosh or PC based?


--------------------
Chuck

[Tom V]

Originally posted by jknights
...FYI According to Fuji, the FinePix RGB 1.8 ICC profile is recommended for use on Mac's as it suits their profile best. It however has a reduced gamut of 1.8. ...

Me thinks you mean it has a Gamma of 1.8. I don't think it is reduced from other gammas, such as Windows standard 2.2, - just different. Gamma refers to the midtones. You can have two images of the same subject with the exposure latitude, same highlight and shadow detail, but different midtone values. I think the one with the gamma of 1.8 would have the lighter midtones.

I use Macintosh.

[Tom V]

Originally posted by cadams
I am occasionally asked to shoot finish samples for furniture manufacturers. ...

cadams,

I used to shoot a lot of furniture. Too much really. In the morning I would get a layout, carpenters would start gathering the set parts (4x8, 8x8, 12x8 wall sections, windows, that c-clamp togethert etc.), I would unroll the carpet roll of choice off the wall, and the set would be built. Decorators would choose the paint, decor, props etc. The set would be painted by about noon and the warehouse crew would set the furniture in place. My job meant hanging up to 40 tungsten lights off the overhead grid using a 14 foot ladder. Around 2pm I would make a test exposure on 8x10 Ektachrome film and bring it to the in-house lab. At 3pm I would review the shot, make color corrections using gel filters, fine tune lights, focus plane, and shoot a range of exposures of perhaps 16, 23, 35, & 55 seconds. By 5, the film would be out, and I would take the film and some of the appropriate furniture parts (cushion, small table or door) to the retouching department. At the end of the day I had a fine portrait of somebody's couch, loveseat and recliner (with ottoman).

[Tom V]

When I shoot color critical products, I try to make my job easier by including items of known color in the shot.

Unlike "normal" photography, shooting swatches or close-ups of furniture, cloth, etc. does not result in an image with a range of hightlights and shadows, or even a range of various colors. You might well end up with an entire frame of reddish wood-grained veneer without a hint as to if it is too red, too light, too yellow, or two dark. If you just let the image go thru without adjusting it, how can you be sure it is acurate?

I shoot with a white/gray/black card in the shot. I make it out of the brightest paper I can find, a new Kodak 18% Gray card, and a piece of black velvet. I include this is the shot so that when I get the image into Photoshop, I will have something of a known standard color to which I can make my exposure and color adjustments. If one side of the frame is brighter than the other, I put the card set on the light side. I shade the velvet in a black tube so no light falls directly on it (I use a lens shade, or black cardboard tube). I suppose there is no reason why you had to keep the swatches all together, but I do. Ideally, the white card should be making up the pixel spike on the right side of your histogram and the black velvet making up the pixel spike on the left side of your histogram, and you would want the gray to be right in the middle.

For the most accurate color I would shoot RAW files and convert them to the Fuji FinePix color space with a gamma of 1.8. I would leave it in that color space unless I had a good reason to change it. For my work, I eventually change it to a CMYK profile (depending on the press and the paper it is going on). I would use lights of a standard color temperture and set the camera to that light temp (ie: tungsten for hot lights, strobe for flash, etc.) I would not shoot with fluorescents or mixed lighting. Turning down studio strobes to very low power can change the color of the light. I would not use polarizers on the lights unless I had to. Make sure you are not shooting thru a warming filter, etc.

When I shot wood products, I wiped the wood down with an oil treatment to bring up the gloss, reduce the glare, bring out the grain, and deepen the color. The deeper color might or might not be what you client wants. Find out first if you should do anything to the wood. To me, using oil on wood is almost like using a polarizer, and it almost always makes wood look more like wood.

In Photoshop's Levels Palette, I use the White Dropper to click on the white swatch, and the Black Dropper to click on the velvet swatch. I figure I don't need any pixels brighter than that bright white, nor blacker than the black velvet. Without these samples to adjust to, there would be no way to set the levels on a furniture sample that was medium tone, with no highlights or shadows of its own.

In Photoshop's Levels Palette, I adjust the color to neutral using the Gray Dropper to click on the 18% Gray swatch. to remove any false color cast.

If the image looks too dark or too light, I would go to the Curves Palette and adjust the middle of the curve by eye. This is where it pays to have a good CDT monitor, hopefully calibrated, or at least predictable to your eye.

In theory, you should shoot all your products with the same set up, lighting and exposure. You then should be able to adjust all you images with the same adjustments in Levels and Curves (you can save your adjustment and use them in other images). Of course, this theory is shot down by products that fall outside the range of the capabilities of the digial camera. Shoot onyx, or white glass, or chrome, or checkerboard neon self-illuminated by black lights would call for some speciallized handling of the exposure and adjustments.

Make sure you dropper is set to sample a 5x5 pixel area, and not a 1x1 pixel area (the default) in order to not be influenced by sensor annomolies.

I would do the sharpening after the adjustments. Sharpening correctly depends on several factors, which may be beyond the scope of this thread. You can adjust the Levels' and Curves' Dropper defaults by clicking on Options in the palette. The default clip is 0.5% but I prefer 0%.

When I am done, I crop the white/gray/black card out.

This was the short answer.;)

[cadams]

Thanks for the reply, Tom.

My shooting method for finish samples is virtually identical to what you describe. I use a standard "copy stand" style of lighting with Speedotron strobes for accurate daylight color balance. I also include a Kodak gray scale which I use in the same fashion as your black velvet, white paper and 18% gray card (to establish neutral color balance and proper density). My question is more to the issue of whether my choice of color space has any implications for the reproduction of the colors on a four color printing press, particularly, if I use FinePixRGB and the commercial printer uses Adobe RGB. It may not make a difference at all, this is simply an area in which I have a lot to learn. I am accustomed to delivering these shots on transparency film. Now I am preparing the digital files and want to make them as accurate as I can. Thanks again!

-------------------
Chuck

[Tom V]

Originally posted by cadams
...My question is more to the issue of whether my choice of color space has any implications for the reproduction of the colors on a four color printing press, particularly, if I use FinePixRGB and the commercial printer uses Adobe RGB. ...

Chuck,

Use the Fuji color space. It should be slightly better than the AdobeRGB for images coming from the S2 via RAW mode. Assuming the commercial printer uses color managment, your profiles will be used as long as they are needed. If they need them in another space they can convert them with the least amount of damage (if any). They might use them as-is, or put them in AdobeRGB or a custom space that they need. A more traditional printer would convert all your RGB images to a particular CMYK color space, depending on their needs, letting the software do the conversions, and outputting the film (to make the plates with). There are different CMYK profiles for different papers, inks, ink coverages, etc. The printer would know what to do with your files in order to convert them to the correct profile. Modern, more digital printing workflows use RGB images right up to the end, and have the output device do the translation to the color space that works best for the printer, paper stock and ink or toner.

You can call the printer (probably the prepress department) and ask what profile they prefer the submitted files in, but my guess is they won't care, because whatever you give them, they translate to their profile anyway. They may have a special profile to give you, or they may say whatever it is in, leave it there.

CMYK is a smaller color gamut than RGB, so don't put it there unless you know it needs to be there. Going back to RGB from CMYK will not recover the lost colors. CMYK file sizes are also 33% larger than RGB, due to the 4th channel.

The printer may ask for proofs made from the files, in which case they probably can suggest a source for acceptable color-accurate proofs ($$$). The printer may like to know what the files are supposed to look like.

[Roadking8]

I now want the long version. Thanks for making some of the unclear clear. How does one economically (ha?) do color calibration for in-house printing. I am assuming that hardware changes (one or all) will happen, and the process needs to be repeated even if it doesn't. So such a system would need to be flexible. Aside from the 18% gray, white and black checks as described, do I need some hardware to read other monitor and printer characteristics?

Road

[cadams]

Just came across a very good article on Color Management by Photoshop guru Ben Willmore. I found it very helpful and informative. It's specifically geared to 6.x (which I am still using), but I doubt much has changed with regard to Color Management in 7.x. Here's a link to the article:

http://www.digitalmastery.com/companionsite/magazine/psuser18.pdf

Chuck