Working space in Photoshop

[jas]

I have done some investigation on how people in the prepress department in my comany have set up Photoshop and how the monitors are calibrated. One thing I have seen is that some people is using the monitor profiles as RGB working space in Photoshop. I have never seen this before and from my experience and what I´ve read thought this was completely forbidden. Why would anyone want to do this? Is the monitor profile not to small to serve as a RGB workingspace?

Edited by: Jon A Sandholt on Mar 3, 2008 10:37 AM

[kyle]

The only reason you would want to do this would be to prepare RGB images for viewing on the same monitor (or perhaps the same make/model). Assigning the monitor's profile to an image (or setting the default space for untagged/unmanaged images) is a way to view images without color management, i.e., whatever RGB values are in the image will be sent to the monitor. Any device space is usually not a good working space because the space is designed to match a device instead of being perceptually uniform. Adobe RGB was made to be a working space, and converting to lab space is usually best for editing purposes (its purpose is perceptual uniformity). If you need a profile to assign to an RGB image for conversion to CMYK (or conversion to a more uniform RGB space), sRGB is probably good because I think it was created by manufacturers to represent an average of monitors (not sure about PC/Mac or LCD/CRT).

[bluskool]

The monitor profile is probably the worst RGB working space to use next to maybe a scanner profile. You want your default working space to be sRGB because when you open an untagged RGB image, you should assume it is sRGB because 99% of the time it is. If your working space is Adobe RGB, then when you open an untagged RGB image, Photoshop assumes the image is Adobe RGB which 99% of the time it isn't. sRGB can be used as an editing space, but would not be the best because its gamut is smaller than what most presses can produce. The best thing to do, IMHO, is to have sRGB as your working space and have photoshop honor embedded profiles, then every time you open an RGB image, convert it to a decent editing space for print production such as Adobe RGB 1998, ColorMatch RGB or ECI RGB. Any of these are good for prepress work, but the absolute most important thing is that everyone in your workflow is doing this for every image that comes in. Now for in house images we use a 16 bit per channel RAW workflow, but that is a whole different story altogether.
As far as using LAB as your editing space, I wouldn't recommend it unless you have a fairly sophisticated workflow and since you have people using monitor profiles as their working space, it doesn't sound like this would be a good option for you. To get any benefit from LAB, you need to be using a 16 bit per channel workflow. Anyway, the hardest part will be convincing everyone else that they are wrong, but it is really necessary to have a consistent workflow.

Dan R.