| | <<<Back 1 day (to 2018/04/11) | 20180412 |
| Robin_Watts | chrisl: You here? | 09:50.08 |
| Rutkay | Hi there! | 11:14.15 |
| | What is the difference between devices with fax encoding (ie tiffg4) and others (ie tiffgray) | 11:14.51 |
| kens | The ones with fax encoding use fax encoding (compression) | 11:15.06 |
| | The others use the specified encoding | 11:15.18 |
| Rutkay | I'm using this generated pdf files with fax operations. Should or must I use fax encoding? Is that a standard or something like? | 11:16.20 |
| kens | There are a number of ITU standards revolving around facssimile transmission (fax) | 11:17.02 |
| chrisl | Robin_Watts: I am here now - btw, sorry for the errant debug code..... | 11:17.34 |
| kens | There are two basic compression methods for fax, CCITT group 3 fax encoding and CCITT group 4 fax encoding | 11:17.37 |
| Robin_Watts | chrisl: No worries. | 11:17.42 |
| kens | They only apply to bilevel images | 11:17.52 |
| | So they can only be used in PDF files if those files contain bilevel images. | 11:18.10 |
| Robin_Watts | I was going to ask about a memory corruption thing, cos it was showing up in freeing the pxl built in font list, but I think it's just random memory corruption. | 11:18.15 |
| kens | (monochrome) | 11:18.16 |
| Robin_Watts | Rutkay: You say you are using the generatated pdf files with fax operations... | 11:18.44 |
| kens | Unless you are creating teh actual binary bits for transmission between fax machiones, you need not worry about it. | 11:18.48 |
| Robin_Watts | Do you mean that you are feeding the fax files direct to some sort of fax software? | 11:19.04 |
| Rutkay | No actually, I'm sending tiff files to another client. It does whatever it want | 11:19.34 |
| | Not specified machine | 11:19.42 |
| kens | OK lets get simpler. | 11:19.56 |
| | You make a PDF file, then what do you do with it ? | 11:20.04 |
| Rutkay | I have pdf files. I'm attaching a bunch of pdf files and merge them basically to send them to another remote client who I don't know anything about. While this pdf operations, I'm using ghostscript to turn this files to tiff and merge and tiff to pdf again | 11:22.17 |
| | I don't know all the details actually :/ | 11:22.36 |
| kens | That wasn't the question | 11:22.42 |
| | When you say 'send them to a remote client' I assume you don't print them out, make little paper aeroplanes and throw them over the fence. | 11:23.15 |
| | So how do you send tehm ? | 11:23.23 |
| Rutkay | As pdf files I think, I don't know transmission details. But I see exactly what I sent on the remote client side | 11:24.41 |
| Robin_Watts | Rutkay: So, let me see if I understood that correctly. Basically you're wanting to merge a bunch of PDF files together in order to be able to send them off to a remote client. | 11:24.56 |
| kens | Well if you don't know the transmission details, why are you asking about fax ? | 11:24.57 |
| Robin_Watts | The mechanism you are using to do this merging is to convert each PDF file to a tiff image, then to create a new PDF file from all those tiff images. | 11:25.29 |
| | Is that correct ? | 11:25.32 |
| Rutkay | Because this operation is named as fax and probably files are being used to get output via fax machines | 11:25.45 |
| | Robin: Yes | 11:26.15 |
| Robin_Watts | Ok, so that's a bonkers thing to do. | 11:26.24 |
| | Don't do that . | 11:26.28 |
| kens | lunches | 11:26.48 |
| Robin_Watts | if you convert from PDF -> tiff then tiff -> PDF you are throwing away data. | 11:26.49 |
| | You will lose quality. | 11:27.00 |
| | A smarter way to work is to use the pdfwrite device. | 11:27.36 |
| | Suppose you have input files in1.pdf, in2.pdf, in3.pdf etc. | 11:28.00 |
| | Then do: | 11:28.03 |
| Rutkay | But in the first place, pdf to tiff causes too much loss. I think I cannot edit all the operation but at least try to not to lose too much data from the beginning :/ | 11:28.08 |
| Robin_Watts | gs -sDEVICE=pdfwrite -o out.pdf in1.pdf in2.pdf in3.pdf | 11:28.22 |
| | That will make you a new out.pdf that contains the 3 input files. | 11:28.40 |
| | Data loss will be as minimal as possible. | 11:28.51 |
| | If the original files contained fax encoded images, so will the output file. | 11:29.14 |
| | The only reason you should *ever* convert from PDF to a fax encoded tiff is if you are going to feed that tiff into something that requires either 1) data that is already fax encoded, or 2) a monochrome image file. | 11:30.53 |
| | That does not sound like your use case. | 11:31.01 |
| Rutkay | I have too much to learn.. I have too old and fragile software to work with it. It's just sad to hear the details | 11:33.16 |
| | Thank you guys, whenever I learn some more details I will come back | 11:36.30 |
| | Forward 1 day (to 2018/04/13)>>> | |
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