I've received the following feedback about Lentigram which I want to post here.
I have a few quick feedbacks;
1) It would be good to have a crop option for testing. For example, we have a 1m x 1m print. After setting everything it would be nice to be able to select any part and size piece and save it with the alignments. For just checking the pitch and color, an A4 print is enough. Now after interlacing we need to go back to photoshop to crop the image. And if we do it we lose the alignments. Or we just need to interlace the smaller portion from the beginning and this means cropping each item before interlacing. If we have a cropping option it would save time and space.
2) On Linux there is "Guten Print drivers" for printers. I have done a lot of tests and used a USB microscope and checked the dots with both Guten Print and a few other RIP software. I can really say that Guten Print prints the most precise dots possible. It is actually maybe better than a really high-end expensive RIP software. It supports a very wide range of printers, especially Epson Printers and has lots of ready precise color profiles. And it's totally free. You just install Ubuntu Studio and you already have GIMP and Guten Print drivers installed.
I have been printing with Guten Print with my Epson Stylus Pro 4900 which is small but very nice 10 color printer. A2 is my max size to print. And it was not a problem until now as I try to print 1m x1m work. I couldn't figure out why, but it crashes when I try to print an image bigger than 80cmx80cm at 720ppi. I have contacted Guten Print developers, they say it is most probably from GIMP. Maybe GIMP can't handle such big files.
Anyway long story short; You already have a Linux version of Lentigram. If you can implement printing directly from Lentigram and make it print big files as much as we require this can be really a turning point in the community. It will help Linux and Guten Print to become more used as they are free software and make Lentigram a more preferred software. And mostly it will help people like me who can not afford a 3000 usd rip software.
My answer below.
The crop function has been in my mind for a while together with a function to remove keystone distortions. I was working on a project
early this month where such a function would have been helpful. I will implement it for sure.
This is the first time I hear about Guten Print and it is very interesting news, especially if you did a comparison analysis under the microscope. I will definitely have a look but I cannot promise because I'm trying to keep Lentigram cross-compatible. For example, I received feedback that Lentigram could run much faster if I implement the interlacing algorithm on GPU. Unfortunately, Apple dropped the support to NVIDIA and it would require too much work from my side to support two different interlacing algorithms. The first thing I will do is to check if Guten Print can work on Windows or Mac too.
If you use a RIP software, in Lentigram you can considerably reduce the size of the interlaced image if you flag the option "Interlacer to keep original image height". That may work for you.