spurssy said:
Well, instead of the numerous "Thank You, Well done" replies, I have a more constructive one here...
I always thought that sRGB is of lower colour space compared to Adobe RGB. So how can an upward conversion lose information? Perhaps I am wrong, but this is good for a little discussion.
Also, for doing test prints, what I typically do is to:
1. Shrink the image and reposition (in Photoshop print preview dialog, you can change the scale and move the printarea around the page).
2. Or Crop out certain area of the image (with most colour information), and repeat step 1.
In this way, you can prob do a x9 or x12 tests with a single piece of paper.
Yes, you'll still lose certain colour information, but not in the form of clipping. Even though sRGB has a smaller gamut than Adobe RGB, because the values of a certain colour (e.g. lime green) in sRGB is different from the values in Adobe RGB, the conversion process requires a programming engine to "map" the colours from sRGB to the same colour in Adobe RGB. However, there are different kinds of "engines" available.
These are usually known as Intents. There's Perceptual, Saturation, Relative Colorimetric and Absolute Colorimetric. They each use different methods to try to map colours between colour spaces. More explanations of the different intents available can be seen in the following url:
http://www.color.org/profile.html
Because these different conversion engines result in different effects, and even though they have the intention of accurately mapping the colours between colour spaces, you'll still get colour information that is different from what you see in the original. So, perhaps it's not so much of "losing" colour information, but that of getting a change in the hues and saturations of the colour information with each colour conversion.
To see what a blind conversion (converting colour spaces without using intents) is like, just go to Mode>Assign Profile... and set a different colour space than your current working one. You'll see a drastic change, whether it be from sRGB to aRGB or the reverse way. To use the different intents, go to Mode>Convert to Profile... and set your intent there.
Try it and see if it works for you, and maybe it'll help you understand more about the colour space conversion. In the guide I was being oversimplistic, so perhaps I should apologise for it. I highly appreciate your constructive feedback, it makes me think a lot! :bsmilie:
