M11-P advice for achieving the best colour accuracy

[otto.f]

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On 10/14/2024 at 2:41 PM, RobW0 said:

@Panchenlama Have you tried setting the white balance from a gray card in the camera? Page 102 of the manual. This will set a custom white balance in camera for the lighting conditions present. I would be interested to know what kind of results you get with this method.

 

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Doesn’t help either. I tested the M11 with a grey card too and it didn’t solve this problem. Reproduction of paintings is a real tough job and extremely critical. I use C1 btw and find it a bit better in this respect than LR but in the end also powerless against this problem. For OP’s critical work the best choice at this moment seems to me a Hasselblad X2D. I have tried out Hasselblad’s app Phocus and it looked promising.
I did not buy the M11 because it is a bit worse than the M10-R, which colors I mostly like but that’s something else as ‘real’. They quite often are a bit too yellow although not as bad as the M10, but they do not have the magenta problem on top of that. Within Leica M the most correct colors came from the M9. Since the industry stepped over to CMOS the colors are not that accurate anymore. The ISO hype sacrificed true colors. A Leica SL… won’t solve this problem either. I must add that I’m not very familiar with Nikon, but sometimes I get the impression that colors from the Z line are more neutral, seems worth a try before stepping over to Hasselblad for 7x the price. 😁

I read somewhere in this forum that instead of trying to correct colors with the white balance buttons, you can also use Levels in C1 and manipulate the separate channels red, green and blue. This gives a bit more grip on the voyage towards more accurate colors.

Edited October 17, 2024 by otto.f

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[pippy]

On 10/14/2024 at 12:14 PM, Panchenlama said:

...I usually set the lights to 5500k and then set the WB on the camera to the same value. When I import the shots, however, they are always skewed towards both yellow and magenta, coming out brown in tone. When I correct the WB in post using a calibrated grey card and the eye dropper, of course it's much improved, but despite hours of fiddling, it never seems quite right to me. There always seems to be some kind of light colour cast or 'veil' over the whole image and if I can get one colour to look right then the others are off...

 

FWIW here's how I go about calibrating colour balance.

The camera is a Canon DSLR with 85mm Canon prime lens and I'm simply using the proprietary Canon 'Digital Photo Professional' software which came bundled with the body. Lights are regular electronic flash units. Each is fitted with a 'Daylight' (supposedly) softbox. All the following pics show the C-Checker with the settings dialogue box(es) superimposed next to the card. The little box which has been highlighted in green (bottom-left) in each frame shows RGB values from grey squares (either third or fourth from top).

First shows initial pic using the same settings from previous shoot - 5700K - when I was using different softboxes. WB Shift panel (highlighted in cyan) is zeroed. As can be seen although the Red and Green channels are identical at 172 the Blue channel is up at 192 indicating the Kelvin temp. is far too low ;

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Bringing the K Temp. up to 6900 has balanced-out the Red and Blue channels (184 / 185) but now the Green channel is low at 178;

 

Keeping the K at 6900 if the Green channel is tweaked to '+3' in the WB Shift dialogue box the tone in the grey box is now neutral at 174 across all three channels;

 

Shooting in this set-up under these conditions and with these settings will result in perfectly calibrated files. Additionally I will often send the photo of the C-Checker along with the finished images as some design teams / printers like to confirm colour-settings as-shot for themselves.

I'm not familiar with C1 / Lightroom but I'm sure there will be the same adjustments available within these packages.

It is worth mentioning that all the above settings are correct for these softboxes and this lens. As mentioned in my previous post if I were to swap to a different lens it might be neccessary to tweak the Colour Balance. I know, for example, that were I to change the 85 prime for my 50 prime I have to add a further +2 Green. Additionally if I swap to different S-boxes I have to start again from scratch...

Hope some of that might be of help.

Philip.

Edited October 17, 2024 by pippy

[Panchenlama]

10 hours ago, pippy said:

I will, of course, try to help as much as possible but it is difficult to advise the OP unless I know exactly how they are going about things at the moment.

Hi Phillip,

Many thanks for your reply.

My current process is as follows:

Set-up camera tripod and lights on preset markings on the floor. Set lights to 5500k, 100% brightness, 0% green/magenta shift. Set camera WB to 5500k, iso 64. Use handheld incident lightmeter to ensure even spread of light across the frame and give exposure settings (usually f5.6, 15). Shoot at f5.6, 15 +/- 1/2 stop using the self timer to avoid camera shake. Shoot a4 color checker target and WB target for each session. The paintings are 170x130cm in size, hanging on the wall, and my overall frame is around 2mX3m. The CT of the lights probably isn't exactly 5500k, but it's very close and the light is incredibly consistent through the shoot and between the two fixtures. No other light sources, and the window is blacked out.

I don't currently shoot with a tether so I then import from the card into my very old version of LR (5), which does not have a dedicated m11 profile, but it does have a lens correction profile for the Summilux lens. I then create a new colour profile from the colour checker target and apply this and the lens correction profile and then I drop the eydropper tool on the WB card target to set the WB. I then also apply two slight exposure gradients (+25) to compensate for the slightly darker areas at the top and bottom of the frame.

Following the above procedure with my old camera (fuji x100f), gave results that looked right to me (if slightly oversaturated) with no further adjustments required. 

The same procedure with the M11 yields results that look soft, dull, flat, muddy, misty and brownish and require hours of fiddling on the various sliders to achieve something passable but still far from ideal. The exposure doesn't seem right, but then the +/- bracketed shots are even worse, the WB is miles off straight out of camera and applying the colour checker profile makes almost no discernable difference - it certainly doesn't correct the WB. Correcting the WB with the eydropper makes a big improvement, but it still feels off. I then fiddle on the sliders for hours getting more and more frustrated at the time and energy I'm wasting. 

My monitor isn't calibrated, but pro shots of paintings on gallery websites look just fine on it and can't seem to achieve the same neutral grey background they have. I've never tried checking/adjusting the individual RGB channels to achieve neutral greys as you suggest - I don't know how to do that.

I've downloaded trials of the current versions of LR and C1, the new LR gives everso slightly better results than my version, but essentially the same problems remain plus my computer can't cope with it so I get a spinning balloon between every single adjustment. With C1 the colour straight out of camera looks very different, better I think, more natural, and the fine detail at 100% view is vastly improved. I haven't yet tried applying the colour checker profile in C1 - it also works fine on my old laptop, no spinning balloons.

What I'm trying to achieve is a simplified workflow with reasonably consistent results across different sessions, where I can send out photos being confident that the colour and exposure is correctly calibrated. Is that possible do you think?

[Panchenlama]

1 hour ago, pippy said:

Shooting in this set-up under these conditions and with these settings will result in perfectly calibrated files. Additionally I will often send the photo of the C-Checker along with the finished images as some design teams / printers like to confirm colour-settings as-shot for themselves.

That looks amazing! Perhaps (probably) I should have bought a Canon...

How do you correctly set/adjust the exposure for your shoots?

[Panchenlama]

5 hours ago, geotrupede said:

 

Thanks! I'll give that a try

[pippy]

6 minutes ago, Panchenlama said:

That looks amazing! Perhaps (probably) I should have bought a Canon...How do you correctly set/adjust the exposure for your shoots?

The choice of camera isn't (very) important and, in point of fact, having been a Leica / Nikon (film) user for a couple of decades I really didn't want to switch over to Canon but when the change to shooting digitally was absolutely neccessary the decision was taken to move because at that time (2008?) the software which Canon had developed was light-years ahead of what Nikon had produced. 16 years down the line I'm still not enamoured by the Canon system but there's no denying that, considered purely as a tool-of-the-trade, it can get the job done supremely well.

As far as setting the lighting / shooting is concerned when artwork is involved it's very straightforward indeed. Copy-lighting is normally the name of the game; one soft-box set to either side of the work being photographed. Confirming matters with a flash-meter I simply balance the lighting powers of the flash heads so that there is complete consistency from corner-to-corner / edge-to-edge / centre. It is fairly important to use softboxes which are identical in terms of size and (obviously) colour-balance.

Philip.

[pippy]

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2 hours ago, Panchenlama said:

...I don't currently shoot with a tether so I then import from the card into my very old version of LR (5), which does not have a dedicated m11 profile, but it does have a lens correction profile for the Summilux lens. I then create a new colour profile from the colour checker target and apply this and the lens correction profile and then I drop the eydropper tool on the WB card target to set the WB. I then also apply two slight exposure gradients (+25) to compensate for the slightly darker areas at the top and bottom of the frame.

Following the above procedure with my old camera (fuji x100f), gave results that looked right to me (if slightly oversaturated) with no further adjustments required. 

The same procedure with the M11 yields results that look soft, dull, flat, muddy, misty and brownish and require hours of fiddling on the various sliders to achieve something passable but still far from ideal. The exposure doesn't seem right, but then the +/- bracketed shots are even worse, the WB is miles off straight out of camera and applying the colour checker profile makes almost no discernable difference - it certainly doesn't correct the WB. Correcting the WB with the eydropper makes a big improvement, but it still feels off. I then fiddle on the sliders for hours getting more and more frustrated at the time and energy I'm wasting. 

My monitor isn't calibrated, but pro shots of paintings on gallery websites look just fine on it and can't seem to achieve the same neutral grey background they have. I've never tried checking/adjusting the individual RGB channels to achieve neutral greys as you suggest - I don't know how to do that.

I've downloaded trials of the current versions of LR and C1, the new LR gives everso slightly better results than my version, but essentially the same problems remain plus my computer can't cope with it so I get a spinning balloon between every single adjustment. With C1 the colour straight out of camera looks very different, better I think, more natural, and the fine detail at 100% view is vastly improved. I haven't yet tried applying the colour checker profile in C1 - it also works fine on my old laptop, no spinning balloons.

What I'm trying to achieve is a simplified workflow with reasonably consistent results across different sessions, where I can send out photos being confident that the colour and exposure is correctly calibrated. Is that possible do you think?

There should be no problem whatsoever with using your M11. I'll come back to using a Leica for this purpose in three paragraphs time...

Oddly enough although having a properly calibrated screen is very important in some ways for what you are attempting to do - and I know this will sound strange - it doesn't honestly make any difference. What you are needing to do is get neutral values on the greyscale areas of your colour checker. As long as everything is balanced then the colours should be 'correct' regardless of how they appear on-screen.

The approach you are adopting sounds very complicated for what should be a straightforward task. I have tried versions of Lr and Capture 1 in the past and didn't get on with them at all so I use the Canon software when shooting tethered and Photoshop for Post-Prod work. When I shoot with my Digi-M cameras everything is done in Ps.

"In the Name of Science"......(😸) - as the colour-checker set up was already there - I took a snap using the 'colour' M camera. I was very curious to see how the camera captured the thing. The camera is an M-D Typ-262 which means that there is no possibility to select any colour settings; the camera will choose how it thinks the subject will be captured. Flash lighting was exactly as used before. Below are screengrabs of the results from this experiment;

First-off is the DNG file as imported into Photoshop's RAW converter program. As can be seen in the dialogue box to the right the White Balance is 'As Shot'. The camera decided that the best temperature setting was 6150K with the 'Tint' slider down at -19. All other sliders are at 0;

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Using the eyedropper tool (third from left top-left of window) to check RGB values I manually adjusted the Kelvin and Tint settings. Kelvin has gone up to 6250, Tint to -32 (all others still at 0);

Processing-out with these settings gives me this JPEG;

The cursor (which didn't get captured in any of the screen-grabs) was in the centre of the grey-square third from top. As can be seen the values for RGB are 176 / 176 / 176 / and for web 80 / 80 / 80. The point of showing this exercise here is that from import to process-out took less than 30 seconds and - AFAICT - the colours acheived by going down this route will be as accurate as could possibly be required.

As mentioned earlier I have no idea where to find similar tools in the programs you have available but it seems like you are going around in circles a litttle bit. If I were you I'd try to discover where these tools are within your software programs and see if they work in the same fashion as the ones in Ps.

If there is anything else where you think I might be able to help please do get back to me.

Philip.

Edited October 17, 2024 by pippy

[pippy]

I forgot to add that where proper screen calibration is concerned although not having an accurate screen won't affect one's ability to set a neutral colour-balance it is very useful in terms of setting colour-saturation and contrast.

Philip.

Edited October 17, 2024 by pippy

[Panchenlama]

Maybe I'm doing something wrong somewhere down the line - I agree it shouldn't be this much hard work, it wasn't with the Fuji x100f.

When I look back at my shots all the DNG files have this brownish tinge (also in C1), but the corresponding JPEGs don't, they are far more neutral in terms of WB - and also 1/3 stop lighter. Is that normal? Have I got something wrong on my in-camera settings?

I've tried reprocessing the DNGs in the latest version of C1 using the color checker method from the video posted previously. The results are far better than what I managed previously, but the colours still seem a little dull/muted, and bumping up the saturation makes them look weird.

When shooting the colour checker target, does it have to be in the same position as the paintings (i.e. on the back wall), or can I bring it (or the camera) forward to get it to fill the frame more? 

Is there a good method for ensuring spot on exposure in a studio setting like mine?

Thanks for all your helpful replies!

 

[pippy]

2 hours ago, Panchenlama said:

1) When I look back at my shots all the DNG files have this brownish tinge (also in C1), but the corresponding JPEGs don't, they are far more neutral in terms of WB - and also 1/3 stop lighter. Is that normal? Have I got something wrong on my in-camera settings?

2) I've tried reprocessing the DNGs in the latest version of C1 using the color checker method from the video posted previously. The results are far better than what I managed previously, but the colours still seem a little dull/muted, and bumping up the saturation makes them look weird.

3) When shooting the colour checker target, does it have to be in the same position as the paintings (i.e. on the back wall), or can I bring it (or the camera) forward to get it to fill the frame more? 

4) Is there a good method for ensuring spot on exposure in a studio setting like mine?

1) I've no idea why your DNG and JPEGs look different. When shooting I've never used both formats to capture images so have never had the opportunity to make a comparison. Nor, in fact, can I nowadays as my 'colour' Digi-M will only capture files in DNG format. Once processed-out my DNG files and subsequent TIFF or JPEGs look identical to the original DNG.

You say you have a "brownish tinge" in your images. How do the colour-values of the neutral squares read? Just in case you aren't familiar with color theory Red, Green and Blue are (light) 'Primary Colours'. Mixing any two Primary Colours gives one of the (light) 'Secondary Colours' of either Orange, Green or Purple. Mixing all three Primaries or any two Secondaries will give a 'Tertiary Colour'; i.e. Brown of some sort. It would be very illuminating to know how the C-Values of the DNG and JPEG files read.

2) Is your screen Colour-Calibrated? If not then trying to set saturation / contrast levels with any degree of accuracy might be tricky.

3) You are going to photograph paintings. You need to check your lighting and exposure values at the place where the paintings are going to be placed. There is little point in checking anything in any place other than where the light being measured is to be used.

4) Use an incident flash meter and check values at the very least at each corner; half-way along all perimeter sides and centrally. With larger works I tend to check at various other points as well. The exposure readings should, ideally, all be identical but variance by a factor of 0.1 (or even, subject-dependent, 0.2 stops) is unlikely to be noticed by anyone not carrying out fastidious checks.

Philip.

Edited October 19, 2024 by pippy

[pedaes]

Philip,  this is a superb tutorial and I applaud you for it. Also your patience!

[Panchenlama]

Here's the colour checker and a painting straight out of camera through LR5 if that's helpful

In LR (and C1), when I use the eyedropper on the neutral squares, each square gives a different WB setting, and even clicking different areas within the same square will give slightly different results. As far as I know neither LR or C1 allows you to set the WB using the RGB channels before importing as you do with PS.

My screen isn't currently colour calibrated

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[Panchenlama]

1 hour ago, pippy said:

4) Use an incident flash meter and check values at the very least at each corner; half-way along all perimeter sides and centrally. With larger works I tend to check at various other points as well. The exposure readings should, ideally, all be identical but variance by a factor of 0.1 (or even, subject-dependent, 0.2 stops) is unlikely to be noticed by anyone not carrying out fastidious checks.

Indeed Phillip, thank you so much for your patience with this, I really appreciate it.

I refuse to believe I can't get good results with the M11 in this context, I just can't understand why the shots straight out of camera are so currently so far from where they should be. 

[pedaes]

22 minutes ago, Panchenlama said:

LR5

Any chance of using latest version of LR? Doesn't £8000 or equivalent camera deserve it?

Edited October 19, 2024 by pedaes

[charlesphoto99]

Seems you've got a perfect storm of variables going on: led lights (which can be wildly inaccurate depending on brand), uncalibrated monitor, and an older version of Lightroom. Can you try a different camera with the same lighting setup? If it is also magenta leaning then it is the lights. Same with monitor - what does it look like on a different one (even iPad etc)? And perfect results SOOC are a myth - I know I have to usually do adjustments for WB and density with copy work I do, no matter how perfect I think I may be getting it in camera (typically with my D850). Post processing is a fact of life, and way too many think they can opt out of it these days thanks to 'smart' cameras. No, the camera is a dumb object - the photographer is the one who needs to be smart. 

[Panchenlama]

40 minutes ago, pedaes said:

Any chance of using latest version of LR? Doesn't £8000 or equivalent camera deserve it?

I just upgraded to the latest version of C1, with better results, but still the same weird purplish hue on import.

[pippy]

1 hour ago, Panchenlama said:

Here's the colour checker and a painting straight out of camera through LR5 if that's helpful...

In LR (and C1), when I use the eyedropper on the neutral squares, each square gives a different WB setting, and even clicking different areas within the same square will give slightly different results. As far as I know neither LR or C1 allows you to set the WB using the RGB channels before importing as you do with PS...

My screen isn't currently colour calibrated...

Thanks for the colour-checker shot. Your colour-balance is miles out and because the RGB all have different values we are in that 'Tertiary' area which is why there is a brownish tinge.

I took the liberty of downloading your Colour-checker picture. Here are the results when it was opened / adjusted in Ps.

As shot. Note RGB readings (from grey box third from left) are 190 / 179 / 185;

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In the version of Ps which I normally use there is a simple 'Remove Colour Cast' tool (NCT is the 'key' short-cut) which involves using the Dropper Tool. Here is the above pic after dropper was used on same grey box. Readings are now 181 / 181 / 181;

 

The image, as can be seen, is very flat (hence the 'muddy-looking' white behind the checker) so the next stage is to adjust contrast-levels.We are looking for a neutral near-white somewhere (RGB in the 240's) and a neutral mid-tone (blacks should be well down too).

In the 'Levels' dialogue box the brighter end of the scale (to the right) has been taken to 241; mid-point left as-is and dark end raised to 9. Here are two grabshots of the reworked image. Top shows readings from the white square and second from the 3rd from left as usual.

The white readings - 245 / 251 / 249 - are a bit off but it's quite usual for the whiter squares to discolour either through age or else just getting slightly dirty. Grey levels are neutral at 190 / 190 / 190;

 

It goes without saying that although this process only takes a minute or so it's far better to zero-in colour-wise before you start to shoot. There's a phenomenon called Crossed-Curves where by adjusting the colour-balance to correct one cast the result is that all the other colours will also be altered which is Not a Good Thing...

As said previously I'm not familiar with the more recent versions of Lr / C1 but surely there is a way to dial-in the correct balance as discussed in post #22?

Philip.

Edited October 19, 2024 by pippy

[Panchenlama]

20 minutes ago, charlesphoto99 said:

Seems you've got a perfect storm of variables going on: led lights (which can be wildly inaccurate depending on brand), uncalibrated monitor, and an older version of Lightroom. Can you try a different camera with the same lighting setup? If it is also magenta leaning then it is the lights. Same with monitor - what does it look like on a different one (even iPad etc)? And perfect results SOOC are a myth - I know I have to usually do adjustments for WB and density with copy work I do, no matter how perfect I think I may be getting it in camera (typically with my D850). Post processing is a fact of life, and way too many think they can opt out of it these days thanks to 'smart' cameras. No, the camera is a dumb object - the photographer is the one who needs to be smart. 

I already have. I got great results previously with exactly the same setup using a fuji x100f, same lights, same settings, also with my old LR5. Import, create colour checker profile, apply profile, eyedropper WB and done, no further adjustments needed and they looked great. No magenta lean. I don't mind post processing, but I feel like I'm not able to get the results I want with these M11 files now matter how much time I spend on them.

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[Panchenlama]

10 minutes ago, pippy said:

As said previously I'm not familiar with the more recent versions of Lr / C1 but surely there is a way to dial-in the correct balance as discussed in post #22?

Philip.

That's extremely helpful Phillip, thank you. I'll try PS, and do some experiments to see if I can get out of camera results that aren't so far off true. I don't understand why they are so wrong. In my (perhaps simplistic) mind setting the WB in camera to 5500k and the lights to the same value, I had hoped to get something that then required very little adjustment - it worked with the x100f. I also don't understand why the contrast is also so wrong...

[otto.f]

24 minutes ago, Panchenlama said:

I already have. I got great results previously with exactly the same setup using a fuji x100f, same lights, same settings, also with my old LR5. Import, create colour checker profile, apply profile, eyedropper WB and done, no further adjustments needed and they looked great. No magenta lean. I don't mind post processing, but I feel like I'm not able to get the results I want with these M11 files now matter how much time I spend on them.

My experience too, in spite of what people may say here about creating your own profile. Before you can save settings as a profile that suits every situation, you’ll have to find that settings. I believe that it has nothing to do with the way of lightning in the studio, Kelvin setting etc. If it doesn’t work with normal daylight outdoor, which is the case with the M11 (and less so with M10 and M10-R), then the problem lies elsewhere and I think the question is: how is the information from the channels interpreted by the camera software in such a way that it is impossible to intervene at that level towards neutral colors. 

Edited October 19, 2024 by otto.f