# Printing large images - help needed!!



## Zv (Dec 29, 2012)

Hey guys, I need your combined wisdom and expertise on this issue - I've been asked to provide two images to a client who wants to put them between 2 panes of glass for a wall mount. The size of the images would be as follows

bathroom : 210 cm x 185 cm

corridor : 263 cm x 198 cm and 247 cm x 198 cm (its in two pieces). 

See pictures that I was sent. 

I mostly have images taken with 18 MP cameras (550D and 7D), and a few with a 21 MP (5D II). 

What resolution is best for this type of thing? Is it even possible to print something that big with 21 MP?? I assume there must be a way. Any help would be greatly appreciated. Thanks!


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## TrumpetPower! (Dec 29, 2012)

The single best piece of advice anybody possibly can give you is to find a quality print shop you trust, to prepare the files so they look their best on your computer, to hand them over to the print shop without mucking about with them yourself, and to communicate with the shop what it is you want.

Different enlargement techniques work best for different printers, wokflows, and more. Your print shop should know what works best for their setup; that's mostly what you're paying them for.

And printing that large is certainly possible with the cameras you describe. If you'd like a preview of what to expect, you can print a full-size crop on your own printer. First scale the image without resizing or interpolating to the final print dimensions; this will decrease the PPI. Then, crop or set the canvas size to your printer's paper size (obviously without scaling). Tape the print to the wall and stand as far back as your expected viewing distance. If you need to stick your nose in the print, you might have a problem, but, with those dimensions, at a few feet or so it should look gorgeous.

Your other option, much much more expensive for a one-off but cheaper in the long run, is to either buy the equipment to do it yourself or use one of those no-frills print shops like the ones in warehouse retail or Internet-only storefronts. You should expect to make many experimental prints before learning what does and doesn't work. If you're going to do a lot of this sort of thing, it's the only way to go...but not if you're only going to do a few every now and again.

Cheers,

b&


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## Zv (Dec 29, 2012)

TrumpetPower! said:


> The single best piece of advice anybody possibly can give you is to find a quality print shop you trust, to prepare the files so they look their best on your computer, to hand them over to the print shop without mucking about with them yourself, and to communicate with the shop what it is you want.
> 
> Different enlargement techniques work best for different printers, wokflows, and more. Your print shop should know what works best for their setup; that's mostly what you're paying them for.
> 
> ...



Thank you for the reply, i will do a test run using a local print shop. Great idea. However final printing will be down to the client, who lives in a different country so i wont have much control over the result.


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## seanature (Dec 29, 2012)

You shouldn't have any trouble making those enlargements with your files, providing the quality of your files is impeccable. If they aren't tack sharp or if there are any other flaws, those flaws will only be magnified. But if you're starting with a very high quality source, you can go quite large. I once made a 400cm tall print from a Canon 1Ds file (11 megapixels) and it turned out quite well. 

I would echo the advice about working closely with the printer and you can do that even if they're in another country. The printer typically knows exactly what they need to produce good results. Talk to them directly. Don't rely on your client to be the middleman. 

If at all possible, help your client choose the printer. Use the internet to find a list of printers close to the area where the print will end up and call them. Even in a short phone call, you can often get a good handle on whether or not the printer knows what they're doing. Call several, but give your client a finalist or two to go visit.

I do this kind of work regularly and in every case, I've provided the printer with a file that I have enlarged myself. I go back to the original RAW file and do a new conversion, turning off all sharpening. If you don't, the enlargement may have ugly halos. I save this conversion as a 16-bit TIFF and run it through an enlargement program called SizeFixer. It's slow – even on a fast machine, the enlargement can take a few hours – but it contains profiles for specific digital cameras. Use the profile for your camera and run the enlargement at the maximum quality setting to the file size that the printer specified.

If the printer is going to apply the final sharpening, I give them the output from SizeFixer. If they're looking for more of a final file to print from, I will over enlarge through SizeFixer (if the printer asks for 240 dpi, I'll enlarge to 300 or 360 dpi), apply some sharpening, and then reduce it to 240 dpi.

But, I can't stress this enough, try to work directly with the printer to ensure you're giving them the best file for the job. You're going to be judged on the final output, so you and the printer need to work as a team to ensure the client is happy.


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## trojdor (Dec 29, 2012)

Zv said:


> Hey guys, I need your combined wisdom and expertise on this issue - I've been asked to provide two images to a client who wants to put them between 2 panes of glass for a wall mount. The size of the images would be as follows
> 
> bathroom : 210 cm x 185 cm
> 
> ...



Z,

You've gotten some pretty good advise already, especially from seanature.

I just fiinished up about 30 such images for trade show booths for the upcoming CES show.
Most printers will suggest printing at about 150dpi for extremely large images. Since we own a large printer, I'll sometimes go to 240-300dpi for the smaller (48inchesx36inches) and save the 150 for the larger booth backgrounds. (15 feet x 45 feet )

Please note two important points: 1. File size goes up exponentially. Doubling a linear dimension will make the the file 4x bigger, etc. I work with many files that are 6 and 7 gigabyte in size. Make sure your workflow supports the room. (And become familiar with photshop's large file format, since the PSD format won't handle it.)

2. I tend to disagree with other comment about 18mp being enough resolution, especially for that 2 wall wrap-around. You really don't have enough resolution without a high quality up-sampling program. I use a 5D2 and one of two programs with photoshop:
Perfect Resize (formerly Genuine Fractals) (http://www.ononesoftware.com/products/perfect-resize/)
and
PhotoZoom Pro (http://www.benvista.com/photozoompro)

Perfect Resize tends to work better for natural subjects, PhotoZoom Pro w/S-spline Max tends to work better for man-made subjects.

The other advise about using raw 16-bit tiff file formats was spot-on, as was finding and working with a good printer. Comments about buying your own printer should be taken with a grain of salt. Our printer was just under $10,000 USD. I believe it uses 12 ink cartridges at over $100 a pop, and two print heads that need replaced about once or twice a year at about $400 USD each. (We won't even talk about the rolls of glossy photo paper you'll consume.) Unless you want to get into the sign/banner business, it's best to focus on your photography. (pun intended)


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## Zv (Dec 29, 2012)

Thanks, I will try and get info about the printer. Great advice about size fixer etc. Need to look into that one day! I know squat about printing btw. I never got round to learning about it, seems overly complex. Wish i could just hand of a jpeg and be done with it! 



seanature said:


> You shouldn't have any trouble making those enlargements with your files, providing the quality of your files is impeccable. If they aren't tack sharp or if there are any other flaws, those flaws will only be magnified. But if you're starting with a very high quality source, you can go quite large. I once made a 400cm tall print from a Canon 1Ds file (11 megapixels) and it turned out quite well.
> 
> I would echo the advice about working closely with the printer and you can do that even if they're in another country. The printer typically knows exactly what they need to produce good results. Talk to them directly. Don't rely on your client to be the middleman.
> 
> ...


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## Zv (Dec 29, 2012)

Wait a minute, I assume these programs for enlarging aren't free? Photoshop alone can't do the job? I was worried about the big one now. Maybe I'm out of my depth on this one. :-\


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## trojdor (Dec 29, 2012)

Zv said:


> Wait a minute, I assume these programs for enlarging aren't free? Photoshop alone can't do the job? I was worried about the big one now. Maybe I'm out of my depth on this one. :-\



No, they aren't free. But they aren't bad, and you only have to buy them once. I assume you're making money in this business since you referenced a 'client'. Think of these programs as tools to help make money.

And don't let the first time learning something panic you. We're all always 'out of our depth' the first time. You'll do fine.


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## TrumpetPower! (Dec 30, 2012)

Zv said:


> Wait a minute, I assume these programs for enlarging aren't free? Photoshop alone can't do the job? I was worried about the big one now. Maybe I'm out of my depth on this one. :-\



I'll again suggest that you leave the up-sizing to the print shop. They've already paid for the software, and they've already figured out which of the various methods available with the various applications provide the best results for files with the types of detail in your images when sent to their printer.

If you up-size it yourself, they're stuck with whatever you give them. If you give them the file at its native size, they can then feed it to whatever will do the best job.

The same goes for color correction.

Again: make the file really shine on your computer, native resolution, and hand it over to the print shop as is, accompanied by a discussion about how you want the final print to look. (What's the expected viewing distance? Do you prefer "crunchy" sharpness, or would you rather preserve fine detail at the expense of a bit of softness? How much noise can you tolerate? That sort of thing.)

I'll also note that up to a doubling of linear resolution there really isn't any significant difference between Photoshop and anything else, and Photoshop does a good job (though not necessarily the best) at all reasonable ranges of extrapolation. Further, all modern printer drivers do their own extrapolation and interpolation, such that you often don't even want to do anything in Photoshop unless you have reason to suspect that the printer driver won't cut the mustard. And, lastly, sharpening (using whatever technique with whatever tool) is a critical part of scaling as well as printing, and it takes a bit of experience to know how to properly sharpen a file for print -- again, experience that your print shop has that you're paying them to have.

Cheers,

b&


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