Legacy ImageMagick Discussions Archive

I presume that you are talking about digitized images.

The best way to preserve a digitized image is to leave it in the original format untouched.

If you will be performing different operations on the image, the answer depends on the tool(s) you will be using.

Nic, I am not really familiar with the composite operator. Would you mind pointing me to the explanation of the "complex" command line and the rationale of the blending using an alpha mask? (I guess it is meant to thicken the black lines by picking more from the gamma-adjusted downsize.)

Yes, I always tell my friends to use linear light downsizing with EWA Catrom or Lagrange, while they keep using USM to (/hoping to) recover the highlight lost after downsizing in sRGB. EWA Catrom is an overkill in most cases, though.

Any sample?

(BTW, should this post be in relocated to the Users forum?)

Too bad that the support of 64bit compile under XP64 had been dropped ....

ImageMagick-6.8.6-10-Q16-x86-dll.exe (18,305,076 bytes)

"The procedure entry point GetErrorMode could not be located in the dynamic link library KERNEL32.dll."

magick wrote:We'll support HCL in perhaps a week or two. Stand by...

Is it implemented in 6.8.5.5?

Depending on the image content, you may also want to refer to the resize algorithms and the gamma issues mentioned in: http://www.imagemagick.org/Usage/filter/nicolas/#downsample For example: convert in.jpg -colorspace RGB -filter LanczosRadius -distort Resize 1100x600! -density 72 -colorspace sRGB ...

fmw42 wrote:That is reasonable, since RGB and sRGB were reversed then. So using -set colorspace sRGB in the older versions is like using -set colorspace RGB in the newer versions.

That's after the reversion of "-colorspace RGB" and "-colorspace sRGB"

any sample image?

I am not sure that process you mention will not work with grayscale images. It fails for me when the input gray images is already non-linear sRGB gray (as per the images for the above post). It worked a year ago when Imagemagick treated gray images (no matter grayscale or "color" images with gray ...

"Gray problems" seem to pop up a while after the other. I try to avoid them by adding "-set colorspace srgb" immediately after the input image. So far it works.

Edit: oops... not for 6.8.4-5

snibgo wrote:Try non-integer arithmetic, ie IM with HDRI. Your three commands then give identical results.

I dun know that limiting would appear in this manner

I have an old 6.7.6 HDRI compile only. Do you know where we can find an updated windows HDRI compile?

henrywho wrote:Yes, I have to lose something, but that should be rounding, truncation or limiting. NOT overflowing to overall brightness

Just checked the formulae .... such "leaking" is built-in .... period .....

Even if it is converted to 8-bit RGB and got rounded or truncated, it should not change the overall "brightness". No. Lab can represent colours that RGB cannot, such as different tones of fully-saturated red. When you convert these colours to RGB, you have to lose something -- either the full ...