Colour Loss in Digital?


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Deming86

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Mar 27, 2008
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SengKang
heys~

Just went for the photograFEAST workshop today and heard from one of the speakers about colour management that digital photographs capture only about 75% of the colours as compared to film SLRs. Unfortunatley he did not mention how do we go about recovering the missing 20-25% of colour. I'm pretty new and I am looking into post processing such as switch to channel sRGB, Saturation, Curves, Levels. But these saturation/contrast the colour doesn't it? Does it refer to the same thing as like 'recovering' that 25% colour loss via digital? Just wanted to post this question and get some advice =]

Cheers~
 

heys~

Just went for the photograFEAST workshop today and heard from one of the speakers about colour management that digital photographs capture only about 75% of the colours as compared to film SLRs. Unfortunatley he did not mention how do we go about recovering the missing 20-25% of colour. I'm pretty new and I am looking into post processing such as switch to channel sRGB, Saturation, Curves, Levels. But these saturation/contrast the colour doesn't it? Does it refer to the same thing as like 'recovering' that 25% colour loss via digital? Just wanted to post this question and get some advice =]

Cheers~

Correct me if I'm wrong, I think you are referring to colour gamut of the devices ? Film using different approach of capturing light has a larger color gamut as compared to digital sensors as what I have learnt. In additional, film receptors also possess a wider dynamic range as oppose to digital sensors.

Color gamut in layman terms refers to how wide a colour spectrum can be recorded by the device. In essence is how red a red your device can record, how blue a blue and so forth for the green. If you have tried to print a 100% red using a printer, you will realise it looks more like orange than red. Years back I was searching for an answer similar to yours and I learn about colour management and the related terminology. Having the world as the absolute color gamut contributor, your eyes known to science has one of the highest colour gamut as a receptor, meaning u see a much redder red than what your colour monitor can produce and definitely much better than what your camera, may it be film based or digital sensor based can capture. There is absolutely no way to recover those lost colors because it's a receptor limitation. If you are reproducing your works on print, you are consider "lucky" because printers CMYK gamut are normally much worse than your monitor and camera sensor. If you own a copy of adobe photoshop, apply a colour proofing using any CMYK printer profile, you will see the colours immediately turn dull.

Colour calibration between ICC profiles for your camera, monitor and printer generally attempt to set you expectation right. Meaning if you cannot print such a RED in your printer, you wouldn't see it so RED in the monitor either. Various colour gamut fitting algorithm such as perceptual, saturation, absolute and relative helps to squeeze and change the mapping so that it will fit into a smaller colour gamut.

Bottomline, you worries about the lost colours as so to speak, you are losing them in each process goes as u get down to hard copies :)

Getting in film may have wider colour gamut, but u probably won't be able to see them as it is on screen after scanning, remember this digital conversion via the scanner is also limited by the scanner colour gamut which is quite bad if you are not using the reown drum scanner which you probably wouldn't wanna spend money on one and rather just get such a scanning service. It's not cheap either. This technique is used on art pieces which colours are normally pretty critical.

Hope these information helps :)
 

I fully agree with what has been mentioned. During the film days, we can get skin-coloured tone on prints developed however currently what we see are mostly light pinklish/orangee skin tone. Too bad, having said that, We need to go with the time as I believe negative film will eventually be history, just like what happened to laserdisc/tape players etc, not forgetting our classic 1.44 floppies.
 

Wow. Thanks for the insight David. Haha, I'm trying to put up a list of things to work on this holidays, with top priority => understanding colours and colour management. Always wondered how the pros can get such wonderful colours of landscapes etc and learnt from my friend one day that it can only done after PP-ing. Say you guys got any books to recommend on colours and maximising them on digital? Would greatly help in my pursuit of better colours =]
 

Well first of all, set expectation right first. If you are heading for WYSIWYG objective, then first get a colorimeter to calibrate your monitor or lcd at least. To be really so called pro in colour management, it's not a cheap solution either. But start reading up, google in the internet will be helpful.

Wow. Thanks for the insight David. Haha, I'm trying to put up a list of things to work on this holidays, with top priority => understanding colours and colour management. Always wondered how the pros can get such wonderful colours of landscapes etc and learnt from my friend one day that it can only done after PP-ing. Say you guys got any books to recommend on colours and maximising them on digital? Would greatly help in my pursuit of better colours =]
 

WHAT! Deming, I'm here buried in lab reports and revision and you go for workshops lol.
 

haha~ life sciences mah~ =D must have life~ and yah i've already calibrated my monitors~
 

Well that is a start for sure, but this is not sufficient if you wanna get WYSIWYG yet.
Actually for the truth even the camera needs calibration :) The concept is pretty similar to
scanner. Scanner will scan a colour calibration chart, then this image is feed into a colour calibration software that will churn out a ICC profile for the scanner. The same theory applies to camera too, but if I'm not mistaken, unlike scanner, camera receptors have dependencies on external light factors such as white balance, ambient light and so forth, so when taking a shot of the colour calibration chart, this factors have to be controlled.

You can easily buy a colour calibration chart online, but for the software, this process normally belong to the pro level and doesn't comes cheap. Seriously, compared to pro software I have came across last time, even the spyder elite 3 is costed cheap :)

My opinion on this colour calibration is as follows:
As general user, you don't need a highly calibrated system because it's expensive to do so. Unless you are earning from colour accuracy, then you may wanna invest in it, because it will take u quite a long while to ROI :)

Set you expectation to not expect real life colours to be reproduced because it is unlikely to happen with current technologies available to consumers :)

Nevertheless, it is nice to learn more about colour management to widen your knowledge on colours :)

haha~ life sciences mah~ =D must have life~ and yah i've already calibrated my monitors~
 

Correct me if I'm wrong, I think you are referring to colour gamut of the devices ? Film using different approach of capturing light has a larger color gamut as compared to digital sensors as what I have learnt. In additional, film receptors also possess a wider dynamic range as oppose to digital sensors.

Colour gamut is a concept that is only applicable to colour reproduction (i.e. printing), not recording. Typical electronic image sensors can actually record a much wider range of "colours" than the human eye or normal pictorial film, as e.g. Leica M8 owners are acutely aware off.

The real question is how well the spectral response of an image taking device approximates the response of the human eye. Since there is an infinite number of spectra that give rise to the same colour, this is a complex relationship that cannot be expressed by a simple number (although that doesn't stop people from trying to do it, often using psychometric weighting methods that are dubious at best and an arbitrary choice of colour samples).

Whether film fares any better than electronic sensors is very doubtful. The colour response of "normal" colour films is determined by a combination of filtering dyes and sensitizer dyes; the photochemical requirements for the sensitizers restrict the choice of dyes. Common electronic sensors rely on colour filters, which can be anything - dyes, interferometric, whatever, without any restrictions.

It is also a fallacy to unconditionally claim film has a higher dynamic range than electronic sensors. Fundamentally, this is not true; many exposure meters precisely work because their electronic sensor has a larger dynamic range than film. One problem is that it is easy to compare apples to oranges. Dynamic range for electronic sensors is usually determined by noise levels for a single pixel; the characteristic curves of film are obtained over large areas and do not reflect noise/granularity at all. If you were to measure the characteristic curve on a piece of film the size of a single electronic pixel, it would be rather poor. On the other hand, by averaging over multiple pixels (reducing spatial resolution), the dynamic range of electronic sensors would go up dramatically.

Finally, electronic sensors are not "digital", and film is not "analog". Common electronic sensors are analog devices, the only fundamental quantisation being the discrete number of photons registered. In "digital cameras", the analog sensor signals get digitized because digital signals can be processed much more reliably and with higher precision than analog signals (i.e. it has nothing to do with the sensor). In contrast, silver halide grains are essentially threshold detectors; the illusion of "analog" response arises from dithering of large numbers of "digital" grains.
 

Colour gamut is a concept that is only applicable to colour reproduction (i.e. printing), not recording.

Okay.. This part I agree because in the wikipedia the exact statement is "In color theory, the gamut of a device or process is that portion of the color space that can be represented, or reproduced". I agree my statement is not very exact, thanks for pointing out. So to rephrase, the reproduction of the scanner or digital camera colour gamut will determine what we get eventually in digital form of the visual entity.
 

I was talking to one of my designer friends who works in advertising, and I blamed a lack of calibration for my poor colour management (lol excuses) and he said "What for? Nobody bothers to calibrate la." How true it is, I wonder?
 

I was talking to one of my designer friends who works in advertising, and I blamed a lack of calibration for my poor colour management (lol excuses) and he said "What for? Nobody bothers to calibrate la." How true it is, I wonder?

to a certain extent yes. because unless u own the whole process, u can't control the final output even with press checks.
 

I think the process is dependent on what exactly one is trying to print. I have a friend in the art industry, when he print his catalog, colour management is put into good use.

If you are doing graphic or images that you in block of colours, one can always turn to spot colours. Following the pantone colour chart via the colour chart, not your screen, wil ensure colour consistency.

to a certain extent yes. because unless u own the whole process, u can't control the final output even with press checks.
 

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