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I need a photo printed at 12x18'', the dude asks me for a file that's 300dpi and 5400x3600. My original raw is much smaller in dimension (12mp camera), should I
1. Enlarge file to this size in pixels and export it with 300ppi
2. Leave original size in pixels and export with 300ppi
3. ?

I haven't printed this big before, so I got no idea whichever is better.
What do you pro's say?

P.S. monitor is calibrated and I'd like to use Lightroom export for this

Talk to the printer usually 300 dpi is the recommended not the only dpi that the printer will print at.

1. If it is a professional photo printer this is the least desirable way. The software in the printer driver on the major machine is usually better at converting pixels to printer dots then anything you can do so upsizeing will introduce noise. (There are exceptions put this is the norm).

2. no point better to set the size to 12x18 and let the DPI float to what ever it is with the 12Mp image.

3. Talk to the printer and number 2, also if they have it export in the printer/paper colour profile.

In general work with you printer.

well a 12mp image should lend you at 240ppi (am i wrong to think that dpi is a press thing?) which should print just fine. so i think interpolating will only add to file size, nothing else.

If i set the size of the file to 12x18 it will enlarge the pixel dimensions, which is basically resampling

Not if you allow the dpi to float and don't allow resizing as

width in inches = width in pixels / dpi

"Genuine Fractals"?

Fabulous piece of software for uprez'ing an image.

Upsample in PhotoShop (Bicubic Smoother)using the 10% rule and export at 300dpi

I've used Genuine Fractals before and it's my plan B, but I was trying to avoid upsizing

Sorry Ryan, I don't understand it
Do you mean to resize into 12x18 and make sure to tick "do not upsize" or something like that?

It's more difficult in lightroom because it doesn't have fine grain control on resizing as lets say PS.

What basically you have to do is either change the dpi without changing the number of pixels, this will change the size of the print. Or change the dimensions without changing the number of pixels this will change the DPI. to fit the new dimensions.

If the 300 dpi is an absolute requirement you could implement an incremental resizing method which will give you good results for up to 300% increase.

Basically use photoshop to a bicubic resize by 103% then do it again at 104% then again at 103% and so on until you reach the size you need. Why this works better then a one-shot resize approach is beyond the scope of this post.

Ok, I am just gonna go ahead with Genuine Fractals, thanks for the input, incremental resizing is beyond my non-technical brain

No need to understand the Why - just have FAITH.
Trust in the Metrix, for he is correct. Although Adobe PS is the Cadillac of digital image processing programs its downsizing and upsizing algorithms leave much to be desired.


Or just use Genuine Fractals.

For what its worth I would stay away from upsizing. I have worked in a number of production studios that were all at one point in time buzzing with the news of Fractal Scaling. Faced with the issue of taking a print as and making it into a poster or a shelf talker into a massive end isle image. Each studio, convinced the account managers to bill the application into the job. All studios were disappointed with the results.

Your printing 12x18 (approximately 19mp if your at 300dpi). The 300 dpi rule is just a guideline for a 150lpi screen. That tight of a screen is rarely used in mags. You can often run at 220 or in some cases lower without a noticeable difference. However that is only if the image is pristine to begin with. If the image is not pixel to pixel sharp, then all bets are off. Another thing to make note of is the viewing distance. You will most likely be at about a three foot distance when viewing a 12x18 print which is very different from a magazine ad which is usually 1.5 feet away or less.

I remember one job I designed for a product launch about 2 years ago. I had to take a 11x17" spread I designed into a 10x10 foot wall ad. The account person in charge was paranoid about the printers request for a 300dpi file. I told my account manager that I'm so sure that request was over kill that if the file I provide doesn't look mint on the wall, I will quit. After the product launch I asked him if he saw any blurring or pixilation. He said no... then I told him the resolution of the background. It was 30dpi not 300dpi. From a viewing distance of 5+ feet you won't notice. We only had enough image for a 30dpi file at those dimensions so thats all we had to work with. Your case isn't as extreme as this one but the rules of perception still apply. You will probably be ok with a 12mp file if its really sharp to begin with.

Bottom line is you can't make information out of nothing. Guessing at pixels is like asking a camera to guess what's outside of the lenses FOV. Its pure speculation and if it could guess, it would not add any real value to an image because of the inaccuracy.

All of this makes sense for self-printing, but how do you tell the person in charge who's asking you to supply a picture in 300dpi and 5400x3600 px out of a 12mp camera? You and I understand that this is complete nonsense without taking into account the media it's printed on, the distance it's viewed at etc... but he doesn't. All he knows is the printer asks for 300dpi and 5400x3600.

Now when I go print at Costco, all I do is make it larger without changing dpi setting, but in this case I need to give them both. Anyway I did go with genuine fractals, but would be interesting to see what's the best solution

Being in the printing industry, yeah we tell everyone "minimum 300 dpi" for any type of printing.

But you do have the right to say "Here's the best file I have available. Just print it anyways" and see what happens.

I've seen some people make what looks like horrible web photos print out half decently, and sometimes the 300 dpi files look like crap.

minimum 300dpi. what is the recommended dpi?

Remember who your talking to when handing off files. Eg, an art director looks at quality of creative content and a prepress worker looks at specs and colour profiles. In the end you need the best possible mix of creative and technical. With interpolation you swing the pendulum over to the technical side. You will put a smile on the prepress artists face but art directors will start to cringe as your softening an image.

As a general rule of thumb you should keep the image in its purist form. That tends to be the resolution it was shot at (or illustrated if thats the case). The only exception I can think of is if the image is heavily modified with compositing or illustrative artifacts. Then you try to work at the highest resolution possible for its intended use and downsize if the file is needed for smaller graphic elements.

BTW, was it an ink-jet print? If so then resolution is even less of an issue. The 300 dpi rule is generally associated with CMKK screen printing.

Hope it worked well for you

where is a good place to print such a size photo? how long do i typically have to wait to get a large size like that printed?

Hi PotatoEye,

I did a test with images taken from a 12mp camera.

First of all, you're not that far off to the requested size of 12x18.

The camera produces 11.8 x 17.733 @ 240ppi.

Just using the Image Size function in Photoshop to change your ppi to 300 with "Resample Image" clicked OFF and selecting the "best for enlargement", will not reduce the quality of your image.

It's such a small percentage that to the naked eye, you nor the printer, will notice.

Do a test yourself and see.

After enlarging, do an Unsharp Mask. Do a couple of tests to see how much UM you will need to make you happy with the result.

At work, we've had worse case uprezzing issues to deal with. Your uprezzing is very, very small so there shouldn't really be any noticeable change to your image.

But do a test for yourself. There are several methods that basically produce the same results. The 10% rule, Genuine Fractals and other apps.

Cheers
Leesa

i'm not a pro at printing high res photos but i have a large format Mimaki CJV30-160 printer at work and most inkjet printers have heaters now for fast drying. i just printed a 5ft. x 8ft. Inukshuk and that took me 15 mins including drying time. if it's printed at high res i'd say double that. but it also depends on how busy the printing shop is. HTH.

http://www.pikto.com/
http://www.torontoimageworks.com/
http://www.fineartprintstudio.com/

These are the 3 labs I've used in the GTA.

After reading your original post, I'm curious to know what dimensions your camera is producing if your final image size you want is 12" x 18".

Not 12 feet x 18 feet?

I think you meant inches not feet right?

thank you mproxas and LeesaM for your input!

" is inches, right?

Yes. So if 12x18 is your final size in inches, then my previous post stands. You're not resizing by a large percentage so you're image will be just fine if you use Photoshop's feature as I suggested.

just to add to the discussion... I just printed a 16"x20" print for my contact show last week.... the original file was out of my 12mp camera, slight crop, processed the image incoming into PS at 300dpi, cropped to the 16"x20" frame that I wanted, and outputted as a TIFF file. The print was on Epson Luster paper at Tricera. Looks faboo...

300 DPI is basically industry standard. But remember this is for high volumes of printing, like on 10,000 postcards, not a one-off fine art print.

Less than that, we'll blame your file if the photo turns out blurry.
More than that, you'll just be wasting your time uploading a larger file to our server.

Sorry lilfunky1, but print volume has nothing to do with image resolution.

I meant that in a way that this is the industry standard for printing companies that do generally large volumes of print... more in that "I don't know if fine-art photography printing has different standards"