Sending images for printing, what resolution should I use?

[psy1280]

I'm going to try to have my DSO images printed on metal. I'm going to be sending jpegs. Can some one tell me what resolution I should send for each print. I'm looking to order something around 12x18 (just an approximate size). I can change the resolution in Photoshop or Topaz Gigapixel AI. I would guess the resolution matters for sharpness and clarity.

 

Thank you,

Joe

[michael.h.f.wilkinson]

I have had several prints made on aluminium, and am very pleased with the result. I usually choose 40 cm x 60 cm (16"x24") and get great results at the native resolution of my cameras (18-20 Mpixel). I would not myself stretch anything artificially. Don't forget, assuming 3500x5250 pixels, 16x24 prints are printed at 218 dpi, which is way below visual resolution, especially at normal viewing distance. You could go to 32"x48" and still have a resolution better than 100 dpi.

[Rossco72]

Wouldn't you just take the resolution of your image in pixels and divide by the size you want out in inches and that's your number? The higher the better, although anything over 600 dpi will likely be lost on most printers.

[John_D]

32 minutes ago, Rossco72 said:

Wouldn't you just take the resolution of your image in pixels and divide by the size you want out in inches and that's your number? The higher the better, although anything over 600 dpi will likely be lost on most printers.

That's what I do. An ex-work colleague who was a very good amateur photographer suggested to me that anything over 300 DPI was pointless. However that was a few years ago now and I'm happy to believe that printing technology has moved on 😁. He also routinely printed images at 100 DPI and got good results.

[Fegato]

I've worked on the assumption of resampling to 300dpi - that's a sort of (high quality) benchmark for printing I think. I'm guessing somewhat less won't be too much of a problem.

[Rossco72]

at 150dpi it should be ok at a reasonable distance but you will see pixelation close up. at 300dpi it should look pretty smooth. At 600dpi it would be like HD on a telly. Some photo printers will do more than 1200dpi

[TakMan]

300DPI for print at the final size (dimensions that you are printing to - even if that means re-sizing up/interpolating in Photoshop. Doesn’t matter if your 300DPI file is bigger than the intended print size to begin with - just take longer to email to the printers). Can get away with 200 or so for things like box-canvas prints, etc as the grain of the canvas hides lower resolution to a point.

If you resize upwards and the image starts to pixelate then you have to decide if you are happy with that, or go with a smaller print, or make sure you stand further away from the finished item when viewing!

Often folks quote 100DPI or so - this is usually for pull up vinyl banners you see at trade shows, etc. I wouldn’t be looking at that for glass/metal prints. Printing onto that media may require higher resolution…

Note that you can get away with some ‘blockiness’ - you should not be pixel peeping a print and should be standing away from it to appreciate - the bigger the artwork the further away you should be standing. I would say that normally adding some glass, especially anti-reflective will hide a bit of upscaling artefacts - but of course you are printing onto metal (so probably no glass in front), so I’d err on the side of caution and keep artwork as sharp as possible, even if that means choosing a smaller picture to hang.

You want to stay away from jpeg as well for ‘art prints’ -  supply a .tif file (ie saved out directly from your original RAW data and not just re-saving/naming a jpeg as the damage will already have been done), 8 bit is fine - again, check as a courtesy with supplier (jpeg obviously compressing, adding potential artefacts, chance of posterisation, etc)

More importantly, see what your printers actually want and see if they prefer the files supplied in a RGB or CMYK colourspace. If you’ve processed your image in RGB (most probably) and they require "four colour process" (CMYK), convert yourself - visually see how the colours change/dull upon converting the artwork from the RGB colourspace (CMYK cannot print all that you see on a RGB monitor) and then adjust that CMYK file back to something close to your original RGB… at least you get a much better idea of what you may get back once printed!

Often printed artwork ‘saturates’ and so the final work is darker than expected. It could help to slightly lighten the darker regions - just bring up your black point… a tad!

Sometimes it’s safer to provide a full resolution CMYK, composite PDF instead of a .tif file - your supplier may have a preference and if you ask, they may be more interested in helping you achieve what you want.

I send printer files out to various publications / printers (although graphics is now not my full time job) and rather than supply a colour profile to each different printer, it is more manageable just to supply with a fairly generic Fogra39 colour profile for print jobs in the UK - your supplier may suggest a more suitable profile for artwork specifically intended to be produced onto metal (or glass) plus the fact that you are Stateside so will probably have a generic US colour profile).

Of course this assumes you have a calibrated monitor that you are working on in the first instance…

Otherwise it really can be a ‘hope for the best’, you may be pleasantly surprised at the outcome (it may just match what you are viewing on screen), or not!

Can you supply them a file and ask them to forward a proof..? This will give you a good idea of how dark the print may be (and perhaps just how much 'out' your screen may be - hence my earlier comment of lightening a tad….

Hope it goes well anyway, colour calibration and printing are rather like imaging - something akin to a dark art !

Damian

Edited November 15, 2023 by TakMan