Hi sinai. I am afraid there is no imagefile or alto in the archive.zip. In order to see what is going wrong we need to see the input data.

Document.zip
Sorry, here they are. No standard Alto but the legacy files from NLI which the code is accessing for the structural information.
Uploading pdf-images.zip…

Correcting what I asked above: a solution that will take into account the size of the fonts should be adapted to each line, not to each block, because the variance in font size happens also inside blocks, especially in Advertisements.

there should not be any issue with font size if the font size is the same over 1 line and the height of an average aleph is bigger than a minimum. lines are normalized to 120 px. it does not matter if your line has a height of 20k pixels or 2k or 200. if it is 20 px it would be too small. and if there are very big letters and very small letters in the same line, then there can be a problem with the SMALL letters due to the normalization, but not with the big letters.

to me your problem is not kraken related but rather rooted in an imperfect conversion of the underlying legacy xmls which are your local project task. the structure is too complex to dive into it from the outside without further explanations. it is even hard for me to understand which XML belongs to which image.

please join me on gitter as this is not kraken related.

on a private channel on gitter