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Fred's film grain

Posted: 2016-11-29T13:00:01-07:00
by wlange
Regarding Fred's filmgrain script under http://www.fmwconcepts.com/imagemagick/ ... /index.php

How to compare real film grain plates with script input values? For example, say I'd like to apply an ISO 800 film grain onto an image. Is there a way to achieve this except for trial and error (i.e. compare with some reference) until it halfway matches? S.o. else might have already done this.

Re: Fred's film grain

Posted: 2016-11-29T14:39:39-07:00
by fmw42
Do you know the mapping from ISO 800 to its film noise characteristics? If not, then trial and error.

Re: Fred's film grain

Posted: 2016-11-29T14:48:54-07:00
by wlange
No. Better using film grain plates then (if it should match certain characteristics). Thanks for your answer.

Re: Fred's film grain

Posted: 2016-11-29T15:05:21-07:00
by snibgo
The appearance of grain depends on the film speed, emulsion type, film developer, contrast of paper and (perhaps most importantly) the quality of the enlarging lens.

In principle, you can scan a print, and use that to adjust an image giving it the same grain texture as the print. I've seen examples online, but I've never liked the results.

Re: Fred's film grain

Posted: 2016-11-29T15:17:38-07:00
by wlange
Yes, that sounds like an unresolved problem. Nothing to get by with a few lines of code. All those apps prentending to reproduce real film looks must be wrong then (at best close).

Re: Fred's film grain

Posted: 2016-11-29T15:20:23-07:00
by Bonzo
There is software available to recreate grain effects, I did try out dxo-filmpack as I had a link to download it in a magazine once for free. But I could not see the point in adding grain.

Re: Fred's film grain

Posted: 2016-11-29T15:37:04-07:00
by wlange
@Bonzo, DxO-FilmPack is a PS plugin (there are many others with similar capabilities), which cannot be applied via command line. DMMD's Photoshop Host SDK might be the way to go, if PS plugins should be used, though.

http://dmmd.net/main_wp/software-develo ... -host-sdk/

Re: Fred's film grain

Posted: 2016-11-29T15:43:16-07:00
by Bonzo
An interesting link but four years old now and only works with jpg files.

Anyway the dxo link was just an example of what I had tried. Good luck with your project.

Re: Fred's film grain

Posted: 2016-11-29T15:57:36-07:00
by wlange
After fiddling around some time I think I will go with creating hald images using GIMP based on my LUTs, then using convert to apply the output to my imagery. I'll then put some noise on top of this using noise plates. I'll adjust the latter by looking at the result rather then trying to match what certain analogue film types are supposed to look. In the end nobody will care if it's say Fuji Superia 800...

Many thanks again.