Printing digital photos: why do (most it seems) print shops only handle PDF not raster formats like PNG?

Question

I am in Sydney, Australia.

My otherwise very helpful local print shop only handles PDF (with limitations as described in this forum posting).

I have so far not found any print shops in Sydney that will print PNG or JPG or even TIFF directly.

Q: Why, when I can send a raster image directly to the modest Brother Laser Printer or HP Inkjet printer in my office, can't/won't (most/many) print shops accept raster images such as digital photos for direct printing ?

I find it difficult to believe that advanced modern printers could not somehow automatically handle raster files and the color from (non-RAW) digital photo formats.

Answer 1

If you are asking about "print shops" in the sense of printing brochures, and other primary text-based material, then yes, I can understand that they only accept PDF: they want the most precise layout possible for text-based layouts (so-called "camera-ready": they can feed your PDF straight into their workflow, generating offset plates from the pages you provide). They will usually not print just one copy, but go for series (up to 1000s of copies).

And for those, jpeg, png and even tiff just aren't going to work: PDF describes a physical page, with precise placement of all elements (including possible crop marks for cutting to size). The others are not in any way linked to a specific paper layout. In addition, jpeg is a horrible format for text.

The confusion stems from this being a photography site, where "print shop" refers to those making physical prints of images only, in various sizes and often on various substrates (paper, simple or fine-art, but also canvas, aluminium, foam core, dibond, etc...). Typical size of a run: 1 copy... Those kind of shops usually do accept jpeg, tiff and png as input, and usually have a standard policy when the aspect ratio of the file differs from that of the requested format.

Photographers don't deal with the other kind all that often, and the requirements for the "input material" are quite different.

Answer 2

Most likely they simply don't want to bother. There is really nothing special they have to do to print the contents of a PDF file.

In contrast, there are choices to be made when printing a image to a piece of paper. What size margins do you want? Should the image be centered and maximized within the margins? Centered on the page? Maximized so that the page is always filled to the margins, possibly clipping in one dimension? Or, do you want it centered and maximized without clipping, possibly leaving a larger than specified margin in one dimension? Or don't preserve the aspect ratio and always expand to the margins?

When dealing with unsophisticated customers, I can see how getting into all these choices is a lot of hassle they can't charge for. Imagine trying to explain the above tradeoffs to someone that doesn't understand aspect ratio, for example. It's simpler (and more profitable) to require the customer to send a PDF file.

Given all that, I suspect your local print shops will take JPG, TIF, and other file formats if you specifically ask, especially when you tell them the details of what you want in their terms up front. In other words, if you can show them that you won't be a pain in the butt unsophisticated customer who expects 20 minutes of hand-holding for a $15 print job, they may be more accomidating.

Answer 3

Note that there is a subtle difference between printing a PDF and submitting a graphics file to a printer (presumably from a computer of some sort, like a PC or a smartphone).

A PDF is a representation of a page where PNG is of an image. The rendering of the page with the image on it is taken care of when you send it to the printer (size, rotation, colors, margin, etc) and the printer need to ask you these things when you submit an image, where the PDF essentially maps to a piece of physical paper. They may not want that or their customers do normally have print ready copy.

Note that some physical printers accept upload of image files using e.g. ftp and print them directly sidestepping the rendering phase in a computer. This usually uses defaults stored in the printer itself.