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retsyo / delaboratory

Automatically exported from code.google.com/p/delaboratory
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control issues in version 0.9 #42

Closed GoogleCodeExporter closed 9 years ago

GoogleCodeExporter commented 9 years ago 
Curves operation close to unusable for all channels at once control. I.e. if we 
need non-colored RGB curve correction we need to set all 3 RGB curves to equal 
form. But current curves control do not have option for applying one curve to 
all 3 RGB channels.

Please add 'RGB' option for curves layer operation for applying 1 curve to all 
RGB channels at once.

No analog of 'levels' tool. It is very hard to use adjustments of brigtness and 
contrast in 'basic' layer tool to get edges of histogram fit required 
positions. Futhermore the 'contrast' adjustment is mid-level-centered in levels 
so no egde of histogram is fixed. May be add 'gain' adjustment that is 
zero-level-centered 'contrast' so user can first use 'brigtness' to set low 
levels to required position and then 'gain' to set highs.
'Gain' control slider may programmically follow current 'Contrast' and 
'brightness' control sliders so user can select which control to use.
Best I like to see 'levels' layer tool with histogram, and white, mid and black 
controls under the historgam like in Photoshop/GIMP. With mid control adjusting 
gamma-correction. For me it is much faster tool to set 'brightness and 
contrast' in compare with current 'basic' layer tool.

All of the controls (sliders) has fixed edge values that is not always enough. 
May be add edit boxes and the sliders left and right positions with ability of 
manual input of control min and max values and auto-saving of these values for 
current user.

Original issue reported on code.google.com by mmm2012m...@gmail.com on 31 Mar 2012 at 9:27

GoogleCodeExporter commented 9 years ago 
Well there are too many issues in one issue to follow.

About the first one - primary feature of delaboratory is to work in multiple 
colorspaces. What you expect is to use RGB colorspace but create curve from 
other colorspace - why? If you want to play with luminance you can try L from 
LAB or L or HSL, there is also K in CMYK. Using combined RGB curve is always 
worse choice.

The basic layer need improvements, I know, this is just a start.

Please also note that there is no 0.9 version, then last one is 0.6.9.1.

Original comment by jacekpop...@gmail.com on 31 Mar 2012 at 10:26

GoogleCodeExporter commented 9 years ago 
"What you expect is to use RGB colorspace but create curve from other 
colorspace - why? If you want to play with luminance you can try L from LAB or 
L or HSL, there is also K in CMYK. Using combined RGB curve is always worse 
choice."

Adjusting curve (gamma) in all channels at once in RGB space is very common 
used transform for enchancing images. It even described in 'creative shooting 
tips for dummies' in the shooting manuals for adjusting video camera's DSP:
1. All levels 'standard' gamma-curve correction - 
http://pro.sony.com/bbsccms/assets/files/micro/xdcamex/solutions/Create_Film-lik
e_Images.pdf
2. Low/Black range levels partial gamma-like correction - 
http://pro.sony.com/bbsccms/assets/files/micro/xdcamex/solutions/Enrich_Color_Sa
turturation.pdf
As I assume both of these corrections are performed in per-channel basis in RGB 
color space (before Y,R-Y,B-Y matrix), because there is a special Y-based gamma 
adjustment (L in HSL space) - 
http://pro.sony.com/bbsccms/assets/files/micro/xdcamex/solutions/Shooting_Pictur
es_w_Black_Colors.pdf . Also as you see in the scheme at the end of this 
document 'gamma and black gamma' sircuits are in RGB channels before Y,R-Y,B-Y 
matrixing.

When we adjust curve/gamma for all 3 RGB channels at once we not only affects 
luminannce (absolute RGB levels), but also change relative proportion between 
RGBs that cause saturation changes. That is not only 'L' correction in HSL or 
'K' in CMYK. But it is simple and useful correction for real images for 
enchancing saturation of colors and increasing contrast where we need.

"Please also note that there is no 0.9 version, then last one is 0.6.9.1."

Oh - I too bad in remembering numbers. Yes - current comments are for version 
0.6.9.1.

Original comment by mmm2012m...@gmail.com on 3 Apr 2012 at 8:30

GoogleCodeExporter commented 9 years ago 
This feature request is quite popular so I will probably create separate layer 
type for combined RGB curve manipulation in the future.

Original comment by jacekpop...@gmail.com on 3 Apr 2012 at 11:11

GoogleCodeExporter commented 9 years ago 
levels have been implemented

Original comment by jacekpop...@gmail.com on 22 May 2012 at 10:36