At 10:05 AM +0100 5/11/04, I G Okorji Esq. wrote: >On 10/5/04 6:21 pm, Jack Lowe wrote: > >> ...A PowerBook display will not >> 'suffice' as it doesn't display as many printable colours as the Cinema >> displays (to use my example). > >This is absolutely wrong, with due respect. The amount of colours any >monitor displays is not necessarily determined by its brand or size. Monitor >colours are determined by the bit depth which ranges from 1 bit depth >(Bitmap) to 24-32 (true colour). The 24 bit depth represents about 16.7 >million colours and this is the highest you can obtain from the very best of >the cinema display ranges. The PowerBook like the Cinema display are both >LCD monitors and they function in exactly in the same principle providing >exactly the same amount of colours.
Hi Folks, I don't want to inflame things further but I thought I'd shed some light on this discussion. 3 channels for RGB at 8 bits per channel = 24 bits = 16.7 million different RGB combinations. A monitor profile will describe which COLOURS are represented by those numbers. Do not get fooled into thinking that RGB values = colours. RGB values need to be sent to a device and observed by a human before they become colours. for a short, light-hearted description, read my "Color of Toast" essay here: <http://www.chromix.com/ColorSmarts/smartNote.cxsa?snid=1005&pid=1.pdg> 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. A few rough numbers for comparison: (all these values are in cubic CIELab) Gamut of human colour vision: 2.2 - 2.3 million colours Gamut of G4 Powerbook: 518,733 Gamut of Apple HD Cinema Display: 928,189 so, even though each of the displays has 16.7 million addressable RGB values, the Apple HD Cinema Display can display almost 410,000 more colours. A significant difference to say the least. It could be argued that the PowerBook really only needs about 19 bits for its display - who wants to start an argument though? A few more values for comparison. sRGB = 909,872 Adobe RGB = 1,320,550 SWOP TR001 = 297,472 ISOcoated from ECI = 400,344 please note, all these values are very rough. They are best used only for broad comparisons. Also, the 32bit files that are available in the Mac and Windows have the 24 bit 3-channel RGB and 8 bits more for an alpha channel. The alpha channel can be used for a variety of things including a mask. 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
