Hi Paul paul-at-mamatus.com (Paul Ellis)::22/10/04::11:34 am:: GMT+0100
>Thanks, Neil. > >While looking at the ECI site I saw ECI-RGB.icc. Is this a more sensible >colour space to use instead of Adobe RGB when outputting from C1 or ACR? > there are resons why that colourspace may be better for a euro workflow, I have a lot of respect for my friend Karl Koch from color-solutions (makers of basICColor software etc. Karl invented eciRGB. It's probably a good thing that it has a D50 white point, for a start. Karl has done some more work on eciRGB recently, more info below. However please be aware that there are lots of things to take into account when choosing an RGB space. Image gamut and output device are the most relevant. However, a straightforward blanket recommendation is not really possible. Karl Koch writes: >>We have created an "advanced" version of the eciRGB working space - >>not an official eci profile though. >> <snip> >>I must say that eciRGB as a working space has proven >>its qualities over these 5 years, but is has a major drawback like >>ALL these working spaces: Its gray axis is defined with a gamma >>characteristic which results in a grayscale compression on one end >>and an expansion on the other. If you start to edit an image in one >>of these working spaces, an increase or decrease of RGB values will >>have different effects in visually perceived brightness, depending on >>your starting point (relative to the L* axis). [he means ANY normal workingspace] >> >>In LStar-RGB this problem has been overcome, the gray axis is defined >>in visually equidistant steps like in Lab (or better L*a*b*), hence >>the name. more: eciRGB is bigger in some areas, smaller in others. I strongly recommend Chromix Colorthink to anyone who wants to know more about profiles and their relation to iage data, specifically gamut volumes. It's great tool. Link at: http://www.colourmanagement.net/profilgear.html At our own seminars (and at GATF Arizona last December) I talked [at length ;) ] about moving data from input colourspaces INTO workingspaces and the damage that can so easily occur if it's not done sensitively. Yes, you can ruin a file by just converting to a workingspace. So many people just push the button and think they have a crappy camera or scanner it's scary. Amazingly no one else I know of ever talks about this! Even ARGB can inflict damaging clipping to an incoming image, eciRGB could also, in some rare cases, damage the image. Most clients I've trained see this as one of the most important steps in learning colour management in order to maintain image integrity. Having spent quite a few years researching this very procedure, I've even devised and made special input profiles for some users just to make this step smoother. ISOcoated.icc and ISOwebcoated.icc both include some yellow which is outside of AdobeRGB, that could matter in certain files, especially since some scans contain yellows not able to be accommodated by A-RGB. Workingspaces are, thus, not easy to specify, one size really does not fit all, there is no BEST workingspace (although one, from my friend Don Hutcheson, does have that name and is pretty good as a prepress space as it easily accommodates the whole of the ISO spaces, Don tells me he has had quite some success with Best RGB at USA ad agencies. It's almost able to contain a whole scanner gamut as defined by Don's excellent HCT scanner targets.) Anyone interested, I can get those HCT scanner targets too. Remember, ICC, in most cases currently (icc v2), provides no perceptual transform INTO a workingspace. That's the BIG issue. hope it helps Best Regards Neil Barstow Consulting in Imaging & Colour Management http://www.colourmanagement.net/ http://www.apple.com/uk/creative/neilbarstow/ =============================================================== GO TO http://www.prodig.org for ~ GUIDELINES ~ un/SUBSCRIBING ~ ITEMS for SALE
