At 9:58 AM +0100 5/12/04, I G Okorji Esq. wrote: >On 12/5/04 1:16 am, Steve Upton wrote: > >> The number of colours that can be represented on a display are mostly >> determined by the colours of the colourants (filters for LCD, phosphors for >> CRTs). The more saturated the colourants the larger the gamut and the more >> individual colours can be displayed. > >But in any event the total number of displayable colour that the human eye >can perceive does not exceed 16.7million colours irrespective of there >combination.
true > The PowerBook G4 displays 16.7million colours (combinations!) >so does the cinema display. not true. Again, don't confuse RGB number combinations with the number of perceivable colours. I can send 16.7 million different RGB NUMBER combinations to a PowerBook display but it will only display 518,733 different colours. This means that 16,258,483 of the RGB numbers are basically "wasted". Another way of looking at this is to say that the entire gamut of 518,733 colours is chopped into 16.7 million separately addressable "chunks". Problem is, the difference between each of these chunks is smaller than is perceivable by humans. So if you glomb chunks together until each blob is just barely perceivably different that the next, you'll end up with 518,733 of them. That explanation is a bit of a stretch but sometimes it helps to break these things down to understand them. (pun intended) To take the explanation to the next step, the gamut of the Apple Cinema Display is also divided into 16.7 million addressable chunks. The chunks are bigger, etc, etc. > >Perhaps, but in most circumstances the additional gamut is not required. That I cannot agree with. If you were talking about the differences between an Apple Cinema Display and a good CRT then perhaps. Many, many colors fall outside of the gamut of the PowerBook display however. It is not a good choice for displaying moderately saturated colours that will be printed on anything but uncoated offset and newsprint. >Bear in mind that colour judgement is somewhat subjective, so if an observer >is pleased with the range of colours he perceives using any VDU and he can >reproduce them as accurately as he perceives them with "his desktop printer >such as Epson 2100" then such additional gamut offered by the cinema display >is "luxury". It is like my Canon cooker that rings and whistles and more but >only gets used as the basic cooker, 99.99% of the time. I agree with the subjectivity part. In fact, we consider our work finished when the client is smiling and nodding. It's their judgement that ultimately decides how far we go in getting a match. I can't agree about the luxury part but again that's subjective. There are (at least) three different ways of looking at workflow: - Input Centric - this is where photographers want to capture as much of the original film (or scene) as possible. They choose larger working spaces (much larger than the monitor gamut) and archive high-bit images for the day when printers catch up with their desires. - Output Centric - this is where offset printers choose working spaces that will contain the gamut of a press and nothing more. Much of their work is done in CMYK (in-gamut by definition) and they wonder why anyone would bother capturing colour that can't be printed. - Display-Centric - this is where people just want what's printed to match what's on the screen. Computer artists, 3D artists, video editors and consumers tend to fall into this group. sRGB is typically chosen as the working space as it tends to match the display gamut fairly closely. It doesn't contain any more colours than the display can show so there are fewer surprises. It sounds like you may be in the Display-Centric group. There's nothing wrong with being in any of the groups and people may change groups depending on their budget or project. It's fair to say, however that people who are entrenched in any one group have a lot of trouble understanding the other groups. Ever try to get an offset printer to try to understand your photographic decisions? > >>From your website you wrote: >> >> any profile can be applied to those Lab values to get the color you want. In >this case, we want the color to go to your printer. When the printer profile is >applied it formulates the correct CMYK settings for each color in your file. A >good quality profile will do a great job of matching those colors within the >abilities of the printer. >> >This is exactly what the supplied profiles that comes with Epson 2100 does, >and if you set it up correctly you certainly don't need a super screen such >as the cinema display. Do you agree? perhaps. If you don't mind not being able to see all your image colors on your display and instead refer to the print as the final form of your work, then yes. To some extent everyone in the Input-Centric workflow does this. Some might just choose to see more of what's in the file and they are willing to pay for it. Sorry about the long-winded post but sometimes it's worth going into this stuff because it's not written down anywhere and you shouldn't be required to figure it all out yourselves. Regards, Steve ________________________________________________________________________ o Steve Upton CHROMiX www.chromix.com o (hueman) 866.CHROMiX o [EMAIL PROTECTED] 206.985.6837 o ColorGear ColorThink ColorValet ColorSmarts ProfileCentral ________________________________________________________________________ -- =============================================================== GO TO http://www.prodig.org for ~ GUIDELINES ~ un/SUBSCRIBING ~ ITEMS for SALE
