Is there Linux software to automatically sharpen appropriately for a given print size?

Question

I'm living almost exclusively in Linux these days, working towards making the transition from Lightroom to Darktable.

One of the applications from my Windows days that I used (and really like) is Qimage, which does an amazing job of automagically sharpening photos for a given print size. I would use Qimage and output to a file as the final step before uploading to sites like Mpix for ordering prints.

Is there a similar application in the Linux world? I've done a bit of searching but have yet to unearth anything. I can always continue to run Qimage in a VM, but would love to have a native Linux app that can perform a similar function.

Answer 1

Unfortunately I can't help you with regards to software recommendations, however keep in mind that to obtain good sharpness on print you will need to take into consideration the paper type - gloss / matt / fine art textured etc. (assuming the image is of sufficient size without major upscaling).

Sharpness settings would vary depending on the lens used for the photo, print size and choice of paper type.

Lens correction profiles: In my case I generally tend to correct lens sharpness issues using lightroom profiles. I was able to locate this resource on Linux libraries for lens corrections: http://www.darktable.org/2015/02/on-lens-detection-and-correction/

Print size: Always ensure that the photo at hand is of sufficient resolution for the desired print size (at 300dpi for optimum quality).

Glossy / Matte paper: Typically matte paper requires more output sharpening. In my case I usually increase microcontrast by a few points additional points when printing on matte.

I'm sorry I was unable to answer your specific query and I hope you find these points helpful.

Answer 2

does an amazing job of automagically sharpening photos for a given print size.

Ok I really do not know what automagically is. I do not know what specific sharpening for a given print size is either.

I was watching the software and it does not do anithing special, in fact in my opinion it has deceiving explanations and examples.

In my opinion use gimp and learn how to use it.

• Define what is the otpimum resolution your favorite provider uses. It will probably range between 150ppi and 300ppi. 200ppi is usually a very good option.

• Define the ammount of sharpening you like, yes, it is a matter of taste.

So Next time you send photos to print, send some controlled test photos, for example:

• Same photo, 3 diferent resolutions without sharpening.

• Same photo, same resolution with diferent sharpenings.

In my opinion users rely on that kind of programs because they are somehow unconfident about taking proper decisions, but in reality they are simple.

• If your images are smpaller than 150 ppi, you probably need a little experimenting in resampling too. I would sugest you only resample images to exactly 200%, not 1xx% or 2xx%.