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Can't get accurate colour from C1

Ben Rubinstein

Active member
Hi,

Shooting with a Leaf Aptus II-8 on a DF. Copy work. Using C1 to tether to and process. It seems that nothing I can do will give me accurate colour and an accurate curve. I've tried all the profiles and curves, to be honest, not even close to 100% or even 80% accuracy. Our screen is an NEC P221W calibrated with a Spyder 4 Pro. Viewing with daylight bulbs.

We need accurate colours, we need tonality to be correct. We can't seem to do it.

I'm assuming the answer is a custom profile?

Help?
 

Godfrey

Well-known member
Hi,

Shooting with a Leaf Aptus II-8 on a DF. Copy work. Using C1 to tether to and process. It seems that nothing I can do will give me accurate colour and an accurate curve. I've tried all the profiles and curves, to be honest, not even close to 100% or even 80% accuracy. Our screen is an NEC P221W calibrated with a Spyder 4 Pro. Viewing with daylight bulbs.

We need accurate colours, we need tonality to be correct. We can't seem to do it.

Help?
Is the Xrite Passport unable to be used with your setup? If you can output a DNG file from the camera or C1, you can use it to calibrate against a Macbeth Color Checker and generate a camera profile that Camera Raw and Lightroom can use. I've found it to be very accurate thus far with my cameras, but I'm not familiar with what's possible in a MF digital back system.
 

Shashin

Well-known member
Have you profiled the camera?

Also, if the viewing lights are D50, then your monitor profile should be D65. I know that sounds crazy, but that will get your environment working right. A D50 monitor is too warm.
 

Ben Rubinstein

Active member
Our screen is profiled to D65.

How do I make a custom profile? I have the Spyder colour chart, same as macbeth/x-rite or whatever they call themselves :D Would love a custom profile and also custom curve but no idea how. I assume there are people who offer the service?

I just tried uncompressing the .mos files and running them in lightroom, even worse. I suppose I could try shooting a colour test chart and using DNG converter build a custom profile but really would like to fix this in C1, the uncompressed raw files are double the size, adobe won't do the uncompressed at all and we're shooting around 1-2tb a month and that's with compressed raw!
 

Godfrey

Well-known member
Our screen is profiled to D65.

How do I make a custom profile? I have the Spyder colour chart, same as macbeth/x-rite or whatever they call themselves :D Would love a custom profile and also custom curve but no idea how. I assume there are people who offer the service?
Check the Xrite website for Passport. They offer both a complete package and complimentary free software only. There are tutorials there.

Again, I don't know whether they support C1 or your MF digital rig.
 

Shashin

Well-known member
As Godfrey stated, the Xrite Passport will build a camera profile. I am not sure about the Spyder. Basically, you photography a known color target and the software builds the profile from the image of the target. The profile software should have a way of selecting devices and you can see if a camera is one of them.

One other thought, I was having a difficult time with my strobes because of a high IR output. Once I put an IR cut filter on my lenses, it cured it. But if you are using hot light, I don't see that a possibility--basically, I had a very bad magenta/red shift that was difficult to correct for.

Is there a particular color that is a problem?
 

Ben Rubinstein

Active member
All of them, the tones are all wrong too.

Just checked on the x-rite site, the passport can only build profiles for programs that use DNG profiles, i.e. adobe.
 
S

Shelby Lewis

Guest
Can you use the free adobe DNG converter to make a DNG... then open it in LR and use passport to create a custom profile? Maybe then, LR would be worth using. Just thinkin' out loud here.
 

Ben Rubinstein

Active member
I tried that actually, for some reason it (Adobe DNG Profile Editor) kept failing on a chart shot with the leaf back even after conversion to dng. Weird.
 

yaya

Active member
Hi Ben, a few points for you:

1. there is a linear curve in C1 that was made specifically for Leaf backs and for creating custom profiles. You need to SHOOT with it and adjust your lights accordingly since it tends to bring the overall luminance quite a bit.

2. As a first step I would try the Color Editor in C1, start with either LF3 Product 5 or ProfotoRGB input profile. You can shoot a Macbeth chart (preferably the SG 256 patches one, but the 24 patches one is a good start, just make sure it is in good condition)

3. The next step would be to use a software such as Profile Maker to generate a new profile for your back and lights

4. If you'd like to try the DNG route, you can export the files from Capture One or if you're using the Leaf Raw Converter you can keep the files compressed, there is a checkbox for that.

Hope this helps

yair
 

Ben Rubinstein

Active member
Yair you are a life saver as always. We have been using the Linear curve from the beginning pretty much. As for the profile, I don't want to try and eyeball it, I'm not good enough for that, can I assume you were referring to the now discontinued 'profile maker' from X-Rite? Will that do it for me using the macbeth chart shot that we will do?

Thanks!
 

Steve Hendrix

Well-known member
Yair you are a life saver as always. We have been using the Linear curve from the beginning pretty much. As for the profile, I don't want to try and eyeball it, I'm not good enough for that, can I assume you were referring to the now discontinued 'profile maker' from X-Rite? Will that do it for me using the macbeth chart shot that we will do?

Thanks!

Unfortunately, there is no current Xrite product that can produce an ICC Profile-based workflow for Camera Profiling. I've messed around with converting to DNG and creating the profile with the Xrite Passport Colorchecker software. Not successful. I preferred the results from the generic profiles in Capture One/Leaf Capture. We've brought this up with Xrite - we'll see where it goes.

But if you can come up with an old copy of Profile Maker, that may be a solution.

Otherwise, I would echo Yair on the choice of Color Space Profiles in Capture One/Leaf Capture (ProPhoto RGB work well). By the way, the use of ProPhoto RGB in this case is not the same as setting ProPhoto RGB as a Color Space via the Export Profile function in Capture One, for instance. In this scenario, it is actually being used as an input profile and works very well (considering it is not a custom profile). You could use ProPhoto RGB as an input profile (via Color Looks in Leaf Capture, Base Characteristics in Capture One), and still utilize Adobe RGB or any other Color Space.

You may also find that editing in Color Editor and saving as ICC Profile from there may further the results or at least get you a closer starting point for certain recognizable color spectrums that responded well to those efforts.


Steve Hendrix
Capture Integration
 
First thing is to use two lights crossed over (right head lights left side), then shoot a grey card and check the luminance is consistent across the grey card by looking at the RGB values.

Take a white balance from a known good grey card and check you have neutral grey across the card. Ensures no colour pollution from the light source or nearby.

Once you have it you need to shoot your colour chart. If the colour chart is glossy then you may need to deal with reflections.

Now you must have no profile or linear profile and stick with that. make sure nothing else defaults in c1, if shooting tethered make sure c1 is not applying any settings. Make sure you've reset everything or that c1 will not copy from last.

Turn off sharpening, moire and noise control

That's the input step

C1 now renders the image poorly initially using the output profile, so the data in the raw file must go though an algo, which I believe will be relative colorimetric, but I recall can be perceptual in the preferences. You mustn't use perceptual for colour accurate work.

Make sure your output is in a wide enough gamut, perhaps adobe, pro photo or bestrgb. Make sure you have 16 bit tiff 100%. Now render to photoshop and see what you've got.

Download the colour reference numbers from the chart supplier and check them in photoshop.

Now you have quantitively assessed your colour accuracy.

-paul
 

Mammy645

New member
I never understood why C1 doesn't include some sort of profiling function (same goes for ACR I guess). Is it really that hard to program?
 

yaya

Active member
Is it really that hard to program?
Yes, very hard indeed...

Profiling for something like a scanner is "relatively" easy since there is one known light source and fewer issues with difference surfaces, difference pigment responses etc.

With a camera you are dealing with many, many variables and the results can be affected by things like metamerism, polarisation and so on...

Also some cameras "see" more than what can be represented on screen or on paper, so you have to take care of that part of the equation as well...
 

Ben Rubinstein

Active member
Steve, thank you for that, you've saved me time messing about with the passport. I've tried with Prophoto, still no good. I really do not want to try eyeballing profile corrections in C1, I think it's just a recipe for problems.

Paul, I had to read it through twice but I see exactly what you are saying, thanks!
 

Geoff

Well-known member
Just to repeat the point about light pollution - check to make sure you aren't getting crossed temperature sources - that will drive you crazy too.
 

Ben Rubinstein

Active member
and also will screw up the colour. I have an x-rite chart and I have the RGB values of what they should be, how do I enter those RGB values for each square to build a profile in C1? The color editior is confusing the heck out of me.
 
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