I routinely scale batches of images (mainly architectural photos) to smaller jpegs and I am currently examining best settings for this. Originals are ~ 7000x9000 px and desired resampled output is limit to 2000 px.
I evaluated several tools but (only) XnConvert seems to handle all requirements. As this app is progressed there are multiple options to consider. Please recommend best practises.
Resample method: currently using plain Lanczos. Are there better options?
Enhance: as photos tend to lose shaprness in resamplae anyway I prefer to compensate with sharpen action. I have currently selected old but popular Unsharp Mask (r1, a1,5, t2) which mostly does the trick. I suppose there aro no better algorithms available? (Original photos are sharpened with Topaz Sharpen.)
Output: jpeg 30 %, DCT floating point, subsampling 4:2:0. XnConvert jpeg-engine seems to be ok, if not best in market. Opinions?
Recommendations for photo scale settings
Moderator: xnview