Mark Roberts a écrit : > Godfrey DiGiorgi wrote: > > >> Selecting a colorspace is not a matter of "which is better than the >> other", it's a matter of how much data you can capture vs editing >> flexibility vs what device will you be presenting a rendering on. >> > > Rule of thumb: Whenever someone tells you that one colorspace is > "better" than another you can be pretty sure that what follows is going > to be nonsense ;-) > (Unless they're saying it's better for a specific application, as in > "sRGB is better for printing to photographic paper" or "Adobe RGB is > better for the Vimfurdler 2355 inkjet printer", etc.) > Indeed!
And I would add that the color space is also better or worse depending on the image itself. For some images (maybe most of your images?) using a wider color space may actually give inferior results. I've imagined a lengthy, but very accurate metaphor for this: Imagine you have a field of land. It is your color space. It contains flowers and trees (each of them is a different color). You want to measure the positions of these flowers and trees in this field (each position corresponds to a given color). You can do so by dividing the field in equal portions, marked by poles. You can't position a tree in the field in a better precision than the distance between two poles. The problem is that you only have a limited number of poles. Now you are given the choice between a smaller field (sRGB color space) and a larger field (ProPhoto). The smaller field is contained in the larger one, so there are trees that are in the larger field, but not in the smaller field (these are very saturated colors.) You want the larger field to get an image correctly measured if important parts of this image (a lot of the trees) are only in the larger field. But this comes at a price. As you still have the same amount of poles whichever field you choose (say 256x256), if the larger field is chosen, more land needs to be covered, then the poles will be planted wider apart from each other. You can measure more land, but with less precision. If you chose to map the larger field, but all your trees are in the smaller anyway, all you get, regarding YOUR trees, is a coarser precision. Therefore, for an image with important detail in saturated colors (flowers?), consider working with a wide color space. If you're pretty sure your image only contains colors with lower saturation (portrait?), prefer a narrower color space and you'll have a better rendition of most of your image. Or, use not 256 poles in each direction, but 65536 (16 bit instead of 8) throughout your workflow, and use wide color space until the very last point. I like to use the highlight preview in ACR, to check that no major parts of the image are color-cropped. This preview changes dramatically for saturated colors depending on the selected color space. I work with sRGB whenever that makes sense, and seldom need any wider. Just my 2 cents (a bit long, but these are Euro cents). Patrice -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net
