I have a sample PDF document which we use for stress testing our application which is based on your compoent and there we have a problem to generate a TIFF B&W - Group 4 - 300dpi rendition from this PDF. The PDF is a 10MB file with 1100 pages.
You can download it from here:
We tested with windows 7 - 64bit and with 5GB RAM - the applicaiton runs as a service and is written with C# - only one thread because there seems to be also a problem with the parallel processing.
We successful converted the the PDF to
150dpi - true color - TIFF LZW - 438MB
300dpi - true color - TIFF LZW - 1,5GB
150dpi - b&W- TIFFGroup 4 - 38MB
200dpi - b&w - TIFF Group 4 - 56MB
but when we try 300dpi -b&w - TIFF Gr. 4 - the conversion is not performed successful and we get an conversion error.
Can you please check this why it is not possible to convert this PDF to b&w - 300 dpi - TIFF gr. 4 when 200dpi is possible and when 300dpi color LZW is possible ?