Large Format Printing - Best Practices

[LelleeBelle]

Hello fellow Adobe enthusiasts!

I did some digging in the forums, but I just wanted to ask about the best way to prepare a Photoshop file for large format print.  For example,  the common number for sharpest resolution is 300 ppi, but most seem to only go as high as 200 ppi in order to reduce file size for these kinds of projects.  I realize that one needs to take into consideration how closely the item will be viewed, but because this is trade show booth graphics most will be standing in pretty close proximity to the graphics.  What resolution should I use?  My next question is whether I need to take anything into consideration when saving the Photoshop file format?  The color mode is CMYK, but do I need to tweak the color profiles or will the defaults suffice?  Also, the file is saving as a PSB rather than a PSD.  This is new for me as I typically work in smaller print format.  I'm assuming this is the same as a PSD, but just better suited for large print...?

Thank you in advance!

[Per Berntsen]

What size prints are you going to make?

Inkjet printing or offset (printing press)?

[LelleeBelle]

This is a three panel booth decor.  The center panel is 117" x 93.5" and the wings are 52" x 47". 

It's a little frustrating because my boss never tells me what the various print companies he works for require for file specs. Nor does he bother to give me their contact info so I can iron out these details.  I ran into a print issue with him in the past because I had to play a guessing game for another project we worked on.  I came here to the Adobe forums and they basically said the same thing that's being said here: talk to the printer to find out how the file should be prepared.  Now I know in the future to ask for the printer's contact info. Sigh.

[postrophe]

Hi

As a professional, my workflow is always the same, knowing Z before starting A

knowing Z, usually involve getting a print sample of a similar job.

knowing Z, mean that I will start ( A ) the job (creative) right.

Doing so, will prove to your employer that you are a professional.

Pierre

[CindyShields]

I find this to be frustrating too. I'm creating 3 meter wide large format graphics with a full image in the background. the vendor often just asks for 300ppi (although they write "300dpi") but I'm certain that a resolution at 100% scale doesn't need to be that high and it taxes my system -- I get the alert that there's not enough memory to complete the action. Ugh. I think it's a language problem because these graphics are being sent to different places around the world. 300ppi is required for offset and seems to be WAY overkill for large format imaging. Other vendors here in the states ask for 75 to 200ppi at 100% scale.

[jdanek]

"Other vendors here in the states ask for 75 to 200ppi at 100% scale."...

Yes.  Actually not necessary to go beyond 75ppi at 100% ( i.e., 200ppi ).  And I agree with you that terminology is very often not correct.  Even the Adobe Photoshop manual refers to DPi, when it should be PPi.  DPi being output resolution; PPi being image resolution.

[D Fosse]

You're right, 300ppi is not required for large format print. That's a myth and in fact a total misunderstanding.

As a rule of thumb, any high-resolution file from a current camera will work at any size. The eye really wants to take in the whole, and so you automatically step back - the bigger it is, the further away. So you end up with the same optical resolution, which is not about pixels per inch, but degrees of arc in your total field of vision.

In some special cases, for effect, you want to give the viewer the option to step really close, exhibits or trade show booths for instance. In that case you can up the resolution by a factor of two or so. So instead of, say, 7000 pixels long side, perhaps 12 000 pixels. That means stitching three or four files.

Anything above that is overkill. In most cases, a ppi figure around 100 is still crisp and sharp when standing really close.

[CindyShields]

I suspect the vendors simply use the 300 number to cover themselves in those cases when people use non-vector path text. This is very helpful though -- I am having problems with overly large image sizes.

[melissapiccone]

PSB... means Photoshop Big. you are making a big file so yes. i recommend 150ppi, but you can probably get away with smaller. RGB should be fine, leave it in CMYK if its already there. trade show graphics, printed on vinyl from an inkjet? inkjets print higher quality at lower resolutions and like RGB. they convert the colors for you.

[jdanek]

You might want to take a look at Adobe's Print Publishing Guide.  A good reference book that explains ( or used to ) levels of gray, printer resolution(s), and image file resolution.  What resolution and color mode ( RGB vs. CMYK ) depends on the actual output device.  I used to work with an HPDesignjet5500 large format inkjet printer.  Deep inside the technical literature for this particular printer is the stochastic screening frequency ( 72 lpi [ lines per inch ]  ).  Given that number, image resolution should be 144ppi at final size ( 72 lpi x 2 ).  The symantics of all of the techical information quickly overwhelms the average user.  Many people in the industry just say "give us image resolution at 300ppi" which is not correct.  The challenge for you is getting image sizes up to large format without losing image resolution.  Every time you enlarge an image 200% you cut the resolution in half.

"What resolution should I use?"   Again, it depends on the RIP and/or output device ( printer ).  You could get away with a resolution as low as 72 ppi using some inkjet printers ( if you have to ) or split the difference and use 108 ppi or use max of 144 ppi ( again, depending on the printer itself ).

"do I need to tweak the color profiles or will the defaults suffice?"  That depends on the printer, type of media used , and the RIP.  I recommend you consult with the person actually printing your large format job, ask them if they need your file CMYK or can RGB be used and, if so, what profile for either one?  Most standard profiles ( the ones that are listed in Photoshop's Color Settings ) are suitable, but again, ask the print vendor.  When the print vendor RIPs your job, they will use their own internal printer profile to output your job.  So, based on their output profile, they will recommend a PS profile that is suitable.

Most Postscript printers and RIPs will accept PSD and / or tiff file formats.

[postrophe]

Hi

Good advise from @jdanek. Try to talk to the pre-press technician, not a salesman.

My workflow is always similar, AKA, I use Photoshop for images, Illustrator for vector elements, compose everything in InDesign (all text is added in InDesign), then output to PDF for printing. (based on my printer specks). An example :

trade show booth graphics most will be standing in pretty close proximity to the graphics.

For a 168 inches (W) X 60 inches (H) I'v send a PDF of 11 Mo for digital printing. (people will be like 2-3 feet from the banner)

Mind you, that was a complex job with lots of images and graphics, my overall folder for the job is 8.8 gig

Pierre