You can quite clearly see the raster compression artefacts of the RhinoPDF output. This was the same for both export as> Rhinopdf, and print>Rhinopdf commands.
The filesize also reflects the compression. The original render JPG was 2000KB, and the PDF including vector linework was ~350KB.
Is there a way to fully control raster compression during RhinoPDF export?
I suppose that, ideally, the dpi setting would take care of that.
In order to support transparency, at some point Rhino started creating png files instead of jpg files when printing to PDF. Because these png files quickly became rather large, we started downsampling the images, especially at larger dpi settings.
In Rhino 7.9, we check alpha values in the images to determine if we can use jpg instead of a downsampled png. I guess that might help in your case. If all goes well, there should be a first 7.9 release candidate available within the next 24 hours but you can also upload a file so that we can take a closer look.
-wim
When exporting to RhinoPDF, the DPI doesn’t make an obvious difference to the compression level.
E.g., I exported the RhinoPDF (print) at 1600DPI and 3600DPI (Save as), but the compression artefacts are quite strong and similar; even though the original JPG was exported at 600DPI.
Not sure if it would be easy, but I believe it would be useful to have the following for RhinoPDF
JPG (lossy), JPEG2000 (lossless), PNG encoding for raster (for those who want Alpha channel transparency)
Compression level options for JPG (lossy) and PNG
To avoid degradation of the raster, I combine the vector and raster information externally in Adobe software; but native support would be useful.
I remember back when I used to work more with inDesign, you had exactly those detailed controls about the picture format exported to PDF. I also remember that I made use of this quite often. This control can have huge impact on file size and quality, especially when it will go to print. Would be nice to have.
Though I also should add that for me, like @wim added, controlling via DPI setting works really well for the type of PDFs I produce. Usually I reduce the DPI from 600 to 300, for large PDFs that need to be sent via Email I even go down to 150.
I have also gotten used to the luxury of controlling the image workflow from InDesign (Optimising Images for Export | Screen and Print Workflow - YouTube).
For me, to have control over the output whether it’s going to be for screen or print is super useful indeed.
The default compression out from Rhino is quite high, and the raster loses quite a bit of detail.
