The Importance of Profile Assignment and Conversions on Color Accuracy
Assigning correct Color Profiles to untagged imagery is critical for your color management success. The Color Settings File in the Adobe Creative Suite provides information to each application in the suite on how to handle color when opening files and documents, the settings file also handles issues like missing or different color profiles from working spaces when opening images in Photoshop.
The Missing Profile
I'm sure you have seen this warning at one time or another.
Well, what this is telling you is that the image you are opening doesn't have an embedded color profile. I like to think of it as not having a name tag, saying it's from this place or that place. If you ignore this you most likely will end up with less than great color.
If you ignore the warning, the image will assume the working color space from Photoshop, in my case the sRGB color space is my working space. This might work out just fine, but it is always good to check other profiles for better assigning.
When you get the missing profile warning, check the
"leave as is" and
hit okay. Now you need to go into
Edit> Assign Profile.
At this point you can select from one of the standard RGB color spaces. There are five typically preset in Photoshop, they are
Adobe RGB (1998), Apple RGB, ColorMatch RGB, ProPhoto RGB and
sRGB IEC61966-2.1.
If you have ever encountered overly saturated red/yellow skin tones when printing a Microsoft Word or PowerPoint document, then you have encountered an incorrectly assumed Adobe RGB (1998) profile on the printers Image processor, or RIP (Raster Image Processor)
What this means is the color content for the image was in the sRGB source colorspace, but the RIP forced the processing of the source RGB as if it were actually Adobe RGB (1998) or some other profile. In other words, the output system assumed an incorrect source RGB colorspace. This is one of the main reasons I use sRGB in our workflows of our RIPs and use it as the working space in Adobe CS application here at AlphaGraphics West Valley. Of course there are more capable RGB color spaces that might be used in your situation, but if you are working with and output Microsoft Office Word and PowerPoint files, I recommend you use the sRGB color space as I suggest. Word and PowerPoint are not considered color-managed programs. The exact same image placed in both programs then printed can produced different results. It is assumed that Office apps are native to the sRGB color space for their working color space. See
Choose Color for Office Files from Prints
How to Choose a Profile for Assigning
[caption id="attachment_2519" align="alignright" width="201" caption="Boo the Cat - Correct Visual Appearance"]
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There is no hard and fast rule for picking a profile to assign. Assuming that your monitor is relatively color balanced and you can predict what the output looks like in relationship to your monitor, you can just visually decide on an RGB profile and assign it. Like I've said before, the profile will most likely be one of the common ones or it would already be embedded in the file from the creator.
Here is an example of an image you can
download here and try assigning.
If you have your
Adobe Creative Suite Color Settings set to warn you if a profile is not embedded, then you will get the warning with this file. The file is in the Adobe RGB (1998) color space, but it's not assigned. Try all five basic RGB color spaces and see what the images look like. I've included the image and how it should look here. If you assign it sRGB the color will look very flat.
CMYK Assignments...
It's is less important to assign profiles to CMYK because the content is already what it is. It might be useful to assign the known CMYK profile for convenience sake and to let you know where it was produced prior, such as an uncoated or coated offset press sheet.
Typically images without embedded profiles are in Adobe RGB or sRGB. When images are saved for the web, sRGB is the profile that the image should be converted to in it's final stage. You can leave images that are not going to the web as they are and just include the profile when saving the file. For now, assign a profile that makes the image look most realistic and pleasing to you, then say Ok.
Next, you will want to convert the image based on your specific needs or where the image is planning to be used in it's final form. If it's going to be an image on the web, then convert the image to sRGB and save it, you can include or not include the sRGB profile when saving the jpeg, either one will work fine in browsers, but one will be slightly larger in file size. If you assigned the image any of the other profiles, make sure you save and embed the profile at that time.
A note about PNG files for web: If you like using PNG files for websites, that's great. You will notice when you save PNG files that you cannot embed a profile to that file format. Therefore it is crucial that if the image is in fact going to the web, you should convert the image to sRGB color space, then save it. The image will have the proper color appearance online.
Profile Mismatch
Another type of profile warning you may get is "the document "name" has an embedded color profile that does not match the current RGB working space" What would you like to do? Usually the reason it's not in the same working space is that it's a screen grab, a scan from a desktop scanner, an image from a digital camera, or it was originally assigned something like Adobe RGB based on the preferences of the content creator or photographer. If the image is in a color space such as a monitor profile, or a scanner or digital camera profile, you should select "Convert document's colors to the working space". Doing this will save you from doing it later or having to convert to sRGB for web work. My working space is sRGB which is the native web space, creating all my RGB content in sRGB ensures that it will display on the web correctly. If you have an image that was in a standard RGB space, like Adobe, Pro or other, leave it in that space unless you are planning to use it on the web, then it's not only okay but a must! You really want to avoid any unneeded conversions to images in order to preserve image quality.
Want to Match the Website to a Printed Piece?
Many assume that you would always want to keep your native content in the RGB color space, then just make sure it's tagged for Web with sRGB. Well, what about a situation where you have a printed brochure and you want the web images to match the printed pieces? It's actually quite simple. After you convert your images to CMYK for layout in InDesign, take and make a copy of those images and convert them back to sRGB. The images will already be clipped down to the CMYK color space and will resemble the printed material on the web. If you are working in an RGB workflow where you place RGB native content into InDesign, then make a PDF for printing in CMYK, you would do the same thing, first convert to the same CMYK color space you made the PDF in and then convert back to sRGB and save for web.
[caption id="attachment_2507" align="alignleft" width="225" caption="Image that is native RGB - Does not match printed piece"]
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[caption id="attachment_2508" align="alignright" width="330" caption="Web and Printed pieces now match after RGB was converted to cmyk and back to sRGB"]
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