Negative to Positive

Questions
1

Hi All,
Just for once found a little time to dig into an activity I have with old photograph images - negatives to be exact. I have a lot of negatives from my photography phase which I discovered can be converted to positive images using graphic apps like Affinity Photo (and several others). I was wondering if anyone has played with these images within Codea ? If not - how would you go about it ? - Any ideas ?

2

What are you talking about. Are you trying to switch around two colors? Can you give an example please?

3

@Dinoball901 - it’s a little more complicated than switching colours. Effectively you have to read each pixel and change the RGB colour properties of that pixel.

It’s not straight forward - have you ever seen colour film negatives ?

4

Sounds like a simple shader to me.

5

@LoopSpace - nice to hear from you again, you are probably right. I need to dig out a few of my negatives and scan them in. If I get it to work I’ll post the code.

6

The best I could find was this Instagram reel showing Lightroom mobile too convert a film negative. https://www.instagram.com/reel/CxQ-F7kuzij/

(I think the same could be done with pretty much any photo software, unsure if the results would be as good as proper film developing)

7

@sim - thanks for the reply. Managed to resolve the issue with Codea (other post re image:get() - I got the syntax wrong). The ad you posted is exactly what I was trying to emulate. It is possible to do it with most of the modern graphics packages, I do it with Affinity Photo. My interest was to see if it’s possible in Codea.

Already managed to partially convert a negative to positive, just need to fine tune the colours now so it’s not a washed out image.

Edit: On the syntax issue the V3 reference quotes the syntax as image.get() whereas the command is image:get() - similar with image.copy() and needs to make clear that the word image is actually replaced with your image name/pointer.

8

Doh sorry, I misread what you were asking for.

Would be cool to see what you come up with in Codea (negative + corresponding color reconstruction)