Acv curves of native ones for Affinity

[Richsul]

Folks,

There are thousands of photographers making platinum prints, palladium, gum, oil prints, resinotype, cyanotype, etc. 

Originally these were historic processes and were made via contact negative. Today, we use a digital negative made in a digital printer. Each process, needs a negative, and the negative needs to be corrected for the process's formula, paper, climate conditions (Key West vs Santa Fe,) and printer and inkset, (Matte Black vs Photo Black,) or RGB, vs grayscale.) Making a curve is tedious and we share them, At Bostick & Sullivan, at Photrio, Alternative Photography, and so on. Many are switching over to Affinity, my favorite too... but... we have to keep a subscription to Photoshop to be able to apply to make a negative on Pictorio. This is nice for Adobe, but not to Affinity's users.

We need to be able to read a ACV correction curve and apply it to a digital image before printing. This is because most of these processes are printed using the blue and near UV spectrum and various inks transmit UV light in a non linear fashion. For instance a tiny amount of yellow increases contrast.

We are in need of Affinity:

Being able to read and apply a ACV curve from Adobe,

Or convert and existing ACV curve to an Affinity curve.

Or at least be able to create a curve in Affinity.

This is done by printing a step wedge and scanning the print and coming up with a correcting value and building a new curve from the corrected values.

A sample curve created this weekend is attached.

Thanks.

-- Dick Sullivan HonFRPS
Honorary Fellow of the Royal Photographic Society
www.bostick-sullivan.com
Santa Fe, New Mexico

 

 

10%pt_AFOplatinumprintcurve.acv

[walt.farrell]

Is there a particular reason you posted this under Feedback for Affinity Designer, rather than Photo?

If not, an administrator might want to move this topic.

[Richsul]

Yes, please move to Affinity Photo, it was my fumbling around finding where the features forum was located. The right church, wrong pew!

 

Thanks

[fde101]

From what I can see, an ACV file is a preset for curve adjustments.  In that case, anything that can be done with an ACV should also be possible with a LUT, which can be applied in Affinity apps using a LUT adjustment layer.

If you can use a Curves adjustment within the Affinity apps to do what you need, you can export it as a LUT then someone else can apply it using the LUT adjustment layer.

Not sure if there is a convenient way to convert an ACV to a LUT?

[Richsul]

Thanks, I'll look into the LUT. What is important would be to port over existing ACV curves. 

Where to find information on LUT? I am on the prowl.

 

--Dick Sullivan

[fde101]

1 hour ago, Richsul said:

Where to find information on LUT?

In general?  All over the internet - example: https://www.shutterstock.com/blog/how-use-luts-color-grading

 

For using them in Affinity Photo:

https://affinity.help/photo/en-US.lproj/pages/Adjustments/export_3dLut.html

https://affinity.help/photo/en-US.lproj/pages/Adjustments/adjustment_3dLut.html