Pro Photo RGB LCDs and editing/viewing

[Make]

Hello, I think I understand pretty much all the basics about color spaces and colormanagement in general. I know that you need to choose your colorspace according to both the colors in your photo and the the media you're going to publish it in. However, there's one thing that I don't understand. How can we see the difference between different colorspaces when viewing images on our monitor in editing programs? All LCDs have a colorgamut that resembles sRGB, which is much narrower than Adobe 98 and certainly narrower than Pro Photo. So how can we see when a photo is actually utilizing those extra colors of a colorspace larger than sRGB? And another related question. If the colorspace of inkjets is Adobe 98 and the colorspace of laser-based printers, that form the image on photographic paper by exposure, is sRGB, when should we use Pro Photo?

Thanks a million for your info!

[Make]

Ha, found the answer myself! Read the part "ProPhoto RGB In Use". http://www.luminous-landscape.com/tutorials/prophoto-rgb.shtml#

[Robf]

Indeed, many LCD's dont have a gamut that exceeds sRGB, but some do. But whilst a gamut may not be visible in it's entirety, a large proportion of it will. The gaps will lead to banding or indiscernable colours.

We use the 2nd most expensive Eizo's, and they are calibrated around 2.2 gamma, but even then, there is a lack of dynamic range in the display thats supposed to be sRGB capable that shows up in highlights or in shadows...so i still question wether LCDs are capable of displaying with good integrity the colours they say they can in the first place. Certainly 4 colour reproductions of images created from sRGB space display tonal range that arent visible on display without banding...which suggests to me that whilst even expensive sRGB certified monitors can display the extents of a gamut of colours, there may be gaps inbetween.

To me, there's still a long road between even high end LCD's and high end CRT's like the sony artisans or barco reference displays...but they dont make them anymore, and even the later blue lacies fell from the curve. We're slowly losing ours due to faults one by one, and the LCD's havent made up the gap yet.

They do offer advantages, with digital input they are sharper, they're more stable in colour terms and often closer to calibration than CRT's (in hue terms).

However subtlety and range is not their strong point.

A bit like digital TV, we're being pushed down a road that offers more for the less discerning masses, but there are gaps appearing when more expert users need or want better performance.

I'm sure LCDs will catch up, there are better LCD/LED technologies in the pipeline that should solve the problem, but i think it will take time for them to get to the street.

You should still look to try and use a wider gamut like Prophoto anyway, as an image will suffer less when pushed in PP than with a narrower gamut space like sRGB. With some experimentation of 8 vs 16 bit or different spaces you may be able to see for yourself where the advantages lie.

Depending on your conversion method, essentially when you convert it samples ranges of colours from your image and makes a calculation from that. By moving to a wider gamut you allow this to happen, but if you stayed in a narrower gamut you might find that shifting a colour leads to banding because based upon that sample there just are some colours that cant be produced. I probably havent explained that bit very well, but if you understand why jumping from 8 to 16 bit to do a colour shift and then back to 8 bit can make a better image than just staying in 8, then your with me.

With photoshop you can always work in soft preview whilst retaining another space to see if things will hold in the target space, but i always try and keep to a wider gamut until i have to convert at the end...checking in preview of course along the way.

With smart objects in PS3 i belive it's possible to hold an RGB file in one space whilst in another RGB space entirely, even CMYK, allowing colour mode specific adjustment layers etc to be used...so you can make adjustments without having to convert.