Canon EOS R inaccurate blue rendering?

[Arteest]

Hey, thanks in advance to anyone who may have thoughts on this. I upgraded to the Canon EOS R in December of 2018. As an oil painter, I use it for taking photos of my finished paintings. I have a system dialed in for doing my best to capture as accurate colors as possible for each painting.

However, I’m finding some issues with the blue spectrum of colors in my artwork photos. The camera seems to be excellent with matching most of the colors in my paintings without much post-editing in Camera Raw and Photoshop. But the blues always seem to lean too much toward cyan. So I’m having to painstakingly select just the blue areas in my paintings to make specific adjustments to those blue areas (usually pushing them toward purple to match the colors in the painting).

Please see the photo at the following link.

https://www.danschultzfineart.com/w.../06/280196F4-5C52-4EAA-8AB8-E601E8CFE31E.jpeg

I’m using:
• the latest EOS R firmware
• Canon RF 50mm F1.2 L USM lens
• Color Checker Passport color swatch card
• Polarizing filter
• Shooting in RAW format
• Adobe Camera RAW 2020 (Mac)
• Adobe Photoshop 2020 (Mac)

Has anyone else noticed inaccurate blue rendering with this camera?

 

[Klaus dk]

What kind of lighting do you use?

 

[Arteest]

What kind of lighting do you use?

I use a mixture of 3000k LED and fluorescent lighting.

 

[Phylloxera]

No wonder you got problems!

Both LEDs and fluos exhibit an uncomplete spectrum of white sunlight.

Use halogene lamps for color repros - or sunlight!


Halogene spectrum




LED spectrum - the pink touch at 450 nm is due to overexposure



.

 

[J A C S]

To me, the "original" looks better but I have not seen the original painting, of course.

There are many things that could cause this:

• The photo might be OK but your computer/monitor may not display it well.
• As mentioned above, the lighting could be the problem. Your eyes adjust to it, and ideally, they will adjust to the displayed image as well but it does not really work like that. Also, lighting with poor spectrum could create worse metameric errors.
• The color profile or the software are causing it. Try other profiles or DPP. You mentioned the color checker but you did not say if you use it to create a profile.
• The polarizing filter is a no-no for a critical color work.

 

[Arteest]

I suspected that my lighting mixture might be contributing to the problem.

I don't think I can get away from using the polarizing filter due to the reflective surface of the paintings. And it doesn't make sense to me that it would alter one specific color range like blue and not the others.

I have been using the color profile I created with the color checker software for my EOS R.

I think I can rule out my monitor as the problem since I've had print work done from my adjusted photos that produced reasonably accurate results (magazine articles, ads, etc.).

I guess I'll focus on trying different lighting and see if that solves the issue.

 

[Klaus dk]

No wonder you got problems!

Both LEDs and fluos exhibit an uncomplete spectrum of white sunlight.

Use halogene lamps for color repros - or sunlight!

- or flash. Flash is close to being a "black body radiator" spectrally.

 

[shleed]

I would also look into what colour profile you're using - Adobe's Camera RAW and LR usually defaults to "Adobe Standard", which will result in colours changing from what you'd expect from the camera. You'll need to change the profile to one that matches your camera.

If it already is, it likely is the lighting. You don't need a polariser (which also affects colours) if you aim the lights at it from an angle so they're not shown in the reflection. Larger softboxes can help too.

 

[Arteest]

I would also look into what colour profile you're using - Adobe's Camera RAW and LR usually defaults to "Adobe Standard", which will result in colours changing from what you'd expect from the camera. You'll need to change the profile to one that matches your camera.

If it already is, it likely is the lighting. You don't need a polariser (which also affects colours) if you aim the lights at it from an angle so they're not shown in the reflection. Larger softboxes can help too.

Thank you -- my next step is to explore the color profiles in more depth to see if I can pinpoint anything. I do have a custom profile I set up for my camera using the Color Checker Passport software.

I suspect the lighting is the issue though, so I'm looking into alternatives for that too....