Legacy ImageMagick Discussions Archive

Thank you Glenn.

Thank you all for the advice. Photoshop makes that a default! What was that about Photoshop? I resize in sRGB space. Even when blowing up pixels, I can't see any difference between this or converting to RGB or Lab before the resize, and then converting back to sRGB. I think colorspace would matter l...

Thank you for the example, but it is difficult to see what you mean. If you can define exactly what you want, it likely can be done. Do you want to add a frame at the end that is an average of the first and last frames? Or a longer transition of ??? frames?

I see the change in the source code http://www.imagemagick.org/download/windows/ImageMagick-windows.zip but the behavior is the same in the new version http://www.imagemagick.org/download/binaries/ImageMagick-6.8.6-7-Q16-x64-dll.exe The fix seemed easy, unless the source didn't make it into the new ...

This is my best guess of what PS is doing. convert infile.jpg ^ ( -clone 0 -colorspace Rec601Luma +level-colors black,red -colorspace HCLp -separate ) ^ ( -clone 0 -colorspace HCLp -separate ) ^ -delete 0,3,4,5 -combine -set colorspace HCLp -colorspace sRGB ^ out.png If you like, I would be happy to...

-modulate in HCLp is not implemented.
viewtopic.php?f=3&t=23811

-modulate works in HCL, but not in HCLp. Searching the source I find 11 instances of HCLColorspace, but only 8 of HCLpColorspace. The instance missing in enhance.c is likely causing this issue. Demonstration of the problem: convert hald:10 -colorspace Rec601Luma Luma.png convert hald:10 -colorspace ...

I guess I don't know enough about PS to know what a Gradient Map is. Is it identical to +level-colors?

I cannot reproduce the white turns black using HCL (or HCLp) problem mentioned in that post and the changelog. It must have been fixed.

Fred, what steps did you do in PS to produce that image?

I did a round trip test for HCLp using a hald. RGB -> HCLp -> RGB Worked great! HCLp -> RGB -> HCLp L is preserved. H is preserved correctly. When hue is undefined (gray, when C=0), it is reset to 0. When L is 0 or QuantumRange, C is clamped to 0, which puts us in the previous case. H is circular, s...

HCL to RGB Invalidly large values of C are ignored. This results in RGB values out of range in both directions. These are clamped. HCLp to RGB When RGB values are out of range, they are scaled in such a way that C is clamped so that H and L may be preserved. Very clever! -compose Luminize uses HCL. ...

Thank you Fred. You always know where to read next. C is simply chroma (MAX-MIN). HSB/HSV and HSL stretch chroma into saturation to fill the interval to create a cylinder. HCL does not stretch C to fill the interval. This means less distortion, but also leaves invalid values in the HCL space. RGB to...

The documentation for Luminize compose is unclear. Hopefully I can research, experiment, and stumble my way to some answers. My hope is that such a compose mode (or color space?) could replace some of my uses of HSB/HSV, HSL, and Lab. Please correct me where I am wrong. Photoshop's Luminosity and Co...

Photoshop has the layer blend modes Luminosity and Color. Does anyone know if these are IM's Luminize and Colorize compose methods, or what colorspace Luminize and Colorize work in (HSB/HSV, HSL, HSLuma)?

EDIT: subject

snibgo and I thought not. Sorry it took so long to demonstrate this clearly.