The "correct" answer is to leave no image untagged but assign/embed something so downstream color management is going to be predictable rather than at the mercy of what person or system gets the file next.
Having said that, encountering an untagged RGB image at least says *something* about the color IQ of the person who gave it to you...that usually means the safest bet is to assume/assign/embed sRGB.
In a perfect world (and how I train folks to approach an untagged RGB image) is to start by assigning sRGB, AdobeRGB, ColorMatchRGB and ProPhotoRGB, roughly in that order, and see which is the most likely candidate (as seen on your proplerly calibrated and profiled display of course!).
Terry
Terence Wyse, WyseConsul
Color Management Consulting, G7 Certified Expert
Since there are formats that don't support tags, and other programs that don't honour tags, there must be a procedure for "incorrect" files... or are we saying .gif, and .png are incorrect under all circumstances?
I use sRGB as my default for untagged images. The reason is that we get a lot of non-professional digital photos from consumer-grade point-and-shoot cameras, and even if they are not technically shooting in sRGB it is pretty darned close. If I default to AdobeRGB, untagged photos tend to look too red.
Dan Curry
Looking for prepress work in the Baltimore area. FusionPro, Apogee, & Prinergy.
In a world where one size fits all, where one is after repeatable results if there is no profile tagged to the image (rather than pleasing or "correct" results)? = sRGB
One could pick sRGB for consumer/office customers, Adobe RGB for graphic designers and Pro Photo RGB for photographers...if you knew who was who...and some photographers use Adobe RGB - so it is really hard to make blind assumptions. Not to mention that in Europe ECI RGB may be more common than Adobe RGB etc.
In a world where you have the luxury to second guess the folk supplying you files? = I use the Photoshop action attached to pick the "most pleasing" result, hand in hand with the info palette set to L*a*b* and or other values (in addition to a profiled monitor preview).
@Steophen oops I didn't put colormatch RGB as an option :S the "newsprint" RGB, there was a period we that was what was in circulation... 15 -12 years ago before the www was stable mind you.
I don't think it is that big an issue Lukas, Apple RGB and ColorMatch RGB seem to have had their day (as has Bruce RGB, Don RGB etc). sRGB would appear to be the low end standard. Sure one can include these two similar 1.8 gamma profiles, however times have changed and I would presume that most OS X users have a monitor more similar to 2.2 gamma than 1.8 (and yes, I know - sRGB is not exactly 2.2 gamma).
Reading over my post, it would appear that I need to update my action to include ECI RGB!
Since there are formats that don't support tags, and other programs that don't honour tags, there must be a procedure for "incorrect" files... or are we saying .gif, and .png are incorrect under all circumstances?
GIF will be in the colorspace of your monitor, by default, won't it? It is incapable of carrying an ICC profile, and so is simply RGB values being sent to your monitor.
PNG, can carry a profile, as Leonard told us on your other thread, but that depends somewhat on the software writing the file. There is a "chunk", as the spec calls it, that is dedicated to ICC profiles, but it may not get written. Without a profiile, PNG is assumed to be sRGB, unless it's grayscale.
GIF and PNG would be "incorrect" for print purposes, in my opinion. The output channels that they would be appropriate for, epub or web, don't support ICC profiles well, if at all, do they?
GIF and PNG are quite common in technical manuals, especially if they are manuals that explain how to use a screen interface. So I would say they may not be "design" files it does not disqualify them as appropriate for certain kinds of print. In reports, courseware, books that accompany a seminar etc they are normal, and printable, if handled correctly.
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What profile is Untagged RGB
Originally Posted by Lukas Engqvist
