Bug 133880

Summary:	Add new tool to emulate some physical filters as used with SLR's
Product:	[Applications] digikam	Reporter:	Robert Small <SmallR2002>
Component:	Plugin-Editor-GmicQt	Assignee:	Digikam Developers <digikam-bugs-null>
Status:	RESOLVED FIXED
Severity:	wishlist	CC:	caulier.gilles
Priority:	NOR
Version:	0.9.0
Target Milestone:	---
Platform:	Debian testing
OS:	Linux
Latest Commit:		Version Fixed In:	8.0.0
Sentry Crash Report:

Description Robert Small 2006-09-10 20:49:50 UTC

Version:           0.9.0-beta1 (using KDE KDE 3.5.4)
Installed from:    Debian testing/unstable Packages
OS:                Linux

I think it would be nice to be able to use 'physical filters' similar to the ones available from most camera shops. Personally I think the most used would be:
- Polarising
- Warm
- Cold
- UV

I don't think that this should be too hard to do, this is how I would do it using a generic image editor:
1 - Duplicate the basic layer
2 - Desaturate (remove the colours) from the duplicate (which is ABOVE the original)
3 - Colourise the the duplicate*
4 - Make the duplicate opaque (see though) to somewhere between 20% and 70%**
5 - That should produce a nice image which looks like it's had a filter applied.

*  Colourise depending on the filter selected and on some (controllable?) algorithm to work out how strong.
** Default worked out by an algorithm but controllable by the user.

Now, pardon me if I've proposed something really dumb, but, I think it'd be nice and quite enjoyably usable. For those who don't understand about filters:
http://www.jessops.com/Products/SearchResults.aspx?searchword=&CatId=194&cl=1-132-194

Comment 1 caulier.gilles 2006-09-10 21:06:57 UTC

Fix me if i'm wrong, but simulate a "Polarising" filter is imposible to do with a computer, because it's relevant of pure optic correction.

Of course, 'Polarising' filter is the better optic tool to improve color rendering during shot.

Gilles

Comment 2 Robert Small 2006-09-10 22:01:59 UTC

Physical filters can't really be reproduced, but, a nice _fake_ should be makable. After all, we have some quite impressive algorithms to create data which isn't there.

We can but hope. :)

-- Robert

Comment 3 Mikolaj Machowski 2006-09-11 13:51:19 UTC

This can be achieved by superimpose templates. I did few experiments
(with positive results) for gradients filters some time ago. I believe
my work was included in some pack of downloadable superimpose templates
years ago.

Comment 4 Robert Small 2006-09-11 13:57:29 UTC

Yeah, some quite nice effects can be produced, I know I've created used the same idea to create 'warm' and 'cold' looks. I know that some of the 'filters' wouldn't be possible, but a few of the others would be nice; and, I think it's pretty much an unique idea.

-- Robert

Comment 5 Arnd Baecker 2007-07-02 21:40:45 UTC

Ad #1, polarizing filter:
Lightzone 3.0.6 claims it can do "Polarization Style, emulates a polarization filter"
http://lightcrafts.com/support/versions/files/category-4.html

Would be interesting to see an example of that in action ...

BTW, an interesting article is here
http://www.adorama.com/catalog.tpl?article=100305&op=academy_new

Comment 6 caulier.gilles 2022-01-15 09:28:14 UTC

Hi Robert and happy new year,

Please take a look in GMic Qt plugin for digiKam image editor to see if this kind of tool do not exists yet.

Best regards

Gilles Caulier

Comment 7 caulier.gilles 2023-03-21 06:48:31 UTC

For all digiKam Image Editor advanced improvements, we will delegate this the Gmic-Qt plugin which is stable enough everywhere to be used in production. It include more than 400 filters to use by photographers.

https://i.imgur.com/OFerL8H.png