Up Sampling to Print Posters

Rebecca from NY, USA, using Photoshop 7 with Windows 98, writes in with:
[Quote:] This is a simple problem I know but can't figure out how to enlarge a photo and have it Print out on several pages ie print the image poster size on an inkjet printer. That is, I have an inkjet that prints 8 x 11" prints and I want to print the image 24"x36" on several sheets and then paste them together sort of thing. Am I making sense? It seems simple but after three hours searching the adobe 'help' I've come up with everything but an answer. When I enlarge the image it just prints one page of that part of a zoomed in enlargement. Can you help? Would really appreciate it. Thanks, Rebecca.
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You couldn't find this in any help files because the people doing the helping have lots of money and have other ways of achieving the same results -- like printing to a wide-format printer -- and they've never had to figure out a solution to the problem.

Upsampling Safely

You know that making such an enlargement will substantially reduce the quality of the image. So by asking this question we're assuming that you understand this and do not mind a degraded image for your final poster. We're also assuming that you cannot re-scan the image at the correct size for the project. (If re-scanning is an option, then do so and skip to the printing section of this tutorial.)

So, if you enlarge an 8 inch photo to 36 inches your resolution will end up around 24 pixels per inch if you don't resample. Unacceptable for most uses, but probably okay for your poster since it will be viewed from a distance. (Posters generally aren't hand-held.) Resampling always adds, subtracts or modifies pixels.

First let's tackle the up-sample problem:

8 inches to 36 inches is roughly a 450% enlargement. We don't want to rely on the print dialog to handle this enlargement because it cannot 'see' the image. Additionally we don't want to enlarge the photo in one 450% gulp. Instead, let's make it in a series of 10% steps. Be forewarned this is going to substantially increase file size and memory requirements. On off-the-shelf computers you will reach a memory out error before you achieve your target.

Choose menu: Image > Image Size

Set the first jump to about 110% to 115% Let the other dimensions go where they will. Make sure Resample is checked and Bicubic is the method. Click Okay.

At this point you'll need to carefully resharpen. For this you should use the Unsharp Mask (USM), which is an art onto itself. The USM gives the appearance of sharpening the image by increasing the contrast between the edges of color areas in the file. Too much will produce halos around elements. Too little will not help the file.
Choose Menu: Filter > Sharpen > Unsharp Mask.

In the resulting dialog you'll see several input fields.

Amount = the percentage increase in contrast between edges.
Radius = the number of pixels to affect around edges
Threshold = the contrast amount at which pixels will be modified

All three factors are affected by the nature of the image, the size of the image and the resolution of the image. None of which have been supplied. So we'll guess the minimums and expect you to experiment with test prints to get the right amount of sharpening.

A low amount setting is appropriate for natural photographic subjects like people. Higher settings can be used for images with flat color areas or sharp edges; like buildings. But be careful.

Start with an Amount of 50 to 60; a beginning Radius of 1 to 3 pixels and a Threshold of 15 to 25. If you see degradation, then reduce numbers.

Resampling an image up-size also sometimes suggests adding a slight amount of Saturation and possibly a contrast adjustment. You be the judge.

Now you can do the next enlargement. This time in the Image > Image Size dialog go ahead and set the next 10 to 15%.

I know, this sounds like a lot of steps to get up to 24 inches. But you'll find that very little degredation takes place if you sample up no more than 15%. Careful adjustments between steps will return the image to near original. After you've stepped up, you'll enjoy a much better image for all your efforts.

Comments

[marshall myers]

okay for those having trouble printing multiple sheets to "tile" into a poster. First let me say I"m using Phtoshop Elements 3.0. Bring the image you want to work with up in the photo editing portion. In the middle of the tool bars and just above the image should be a button "Create". Click that and that should bring up an entirely NEW window with the image inside ( labeled Photoshop Elements 3.0 Organizer ). Here there is a "print" button ( just below the file menu labeled "Window" ). The "print" button has a drop down menu on the bottom corner, and I chose "print" NOT "order prints".
Now a NEW window comes up and NEXT TO the "choose printer" box is a tiny little printer preferences window WHICH IS NOT like any other. Under the "finishing" tab and half way down it should say pages per sheet and posters, and THERE you can choose the number of sheets an image is printed on. I hope this is helpful. ( by the way I'm printing to an HP series 6100 which is the scanner/fax/printer combination ink-jet).
Marshall

[Christine Thomas]

Im completely knew at all of this sorry. I have a jpeg file (size 6" x 4" with 384 resolution). I have started up a canvas printing business where the image will wrap around the borders of the frame. The image at the sides of the frame will use approximately 2" of the final printed image all the way around. I am offering set sizes of printing at 16" x 12", 24" x 16" and 34" x 24" as 24" is the largest width size i can print on my wide format printer. I have two questions one about setting the print size and one about the resoluton. First of all - as with the 6" x 4" jpeg file mentioned above - if i want to print this at 34" x 24" as offered (including borders)how do i set it to print exactly that size when the dimensions arent proportionate? Do i change them in the print option and change it to custom and set it at this size? or should i change it in the photoshop image size to improve the resolution? If I do it in image size it automatically changes to 34" x 22.667" but will it then be smaller than 34" x 24"? Or if i deselect the resample image and type in 34" where again it defaults to 22.667" but the resolution reduces to 67.765 (is that the better option for good image as im enlarging it so much)? My other question is much more complicated i think. The image I mentioned is a flower and as the petals are so near the edge I have played around in photoshop and mirrored the edges so that in theory only these edges will wrap around the frame as a border. But how do i know how much of the canvas to select all the way around and mirror from the original image. In other words I just want the mirrored edge to print at 2 1/2" and no more so that the original image is the full picture when looking face on. Hope ive not confused you? But also in order to have workspace to mirror the image i actually made the canvas size bigger as i just thought this was a working area only so although after 6 hours! i finally managed to figure out how to mirror the edges which looks fantastic - i then saved the image as a new jpeg file but when I now open it i now have all the white excess canvas space which i think is going to print?? I dont want to print it just yet as ive wasted so much canvas already practising so was wondering if you can advise on that one too? Any advice on any of these points would help if it makes sense? thank you

[anonymous]

Just open Excel and insert the image, if you go to print preview, you should see that the image is gonna be print on several pages.

cheers

[J. Miller]

What you’re trying to achieve here is call "Tiling" I don’t think there is an option in PhotoShop that will allow you to do this.. Except for cutting the image into pieces like suggested by MasonMouse.. Actually I was going to suggest the same or similar approach. However, it is a standard feature in Quark XPress which will definitely take a PhotoShop file, and definitely save you alot of time and work. If you have access to it I'd use it.

[J doherty]

I am having problems printing a large poster for my photography project (MA Media), I have had most versions of Adobe for PC, but my Lap Top is in the PC clinic suffering from some fucking virus. What I usually did on the lap top, was created the image in any of the Adobe programs, then tranfered them to Publisher XP, in the chose blank publication option, there it is POSTER...format, and publisher cost a hell of a lot less than the Adobe CS for the Imac I work on at home...So if you're willing to rattle a mate with a PC and publisher and don't mind buying the ink...then you can poster away till your hearts content...Oh, when you export from whatever adobe programe you're using, use the exportable giff option, this reduces the size and not the quality...(arguable). But the result is a couple of A2's and an A1 on my bedroom wall...
I wish I had my PC back...or that Adobe and Apple would get their heads out of thier asses and write a little program mirroring the poster function on MS Publisher XP

[Michele]

I've been playing around with Photoshop 7 trying to enlarge an 8 1/2 X 11 party invitation to poster size (24 X 36). I even bought Photoshop 7 for Dummies and still can't figure it out. Some how, while clicking this and that, the program printed my image on 9 pieces of 8 1/2 X 11 paper. The image quality was more than acceptable. This was just great and figuering I could simply do it again, I trimmed the pieces together to make a poster. It looks OK but there are too many seams. I want to do it again on 8 1/2 X 14 paper but now, of course, I can't duplicate the print job. I can only print a single page of a portion of the image. Can you tell me what I did the first time?

[JT]

How to print a large image on several pages.
Use this: http://www.aceposter.com/ it works great and is only $9.

[MasonMouse]

I've been trying to figure out how to do the same thing. I tried importing images from Photoshop to PrintShop but the latter program just isn't made for DTP and it doesn't work well.

So what you might try is find out what the actual printable dimensions of your printer are and divide the picture up into however many tiles it takes to print.

For example, my HP 870Cse here has margins of Top: 0.04" - Bottom: 0.46" - Left: 0.25" - Right: 0.25" which means I can print on exactly ( 8.5" - (left margin + right margin)) 8" by ( 11" - (top margin - bottom margin)) 10.5" so an 8" x 10.5" image on 8.5" x 11" paper.

I'm using Photoshop 6.0 so the exact instructions may vary but I open my poster size image (21.75" x 33.75" in my case) and go to View > New Guide and Check Horizontal and enter 10.5 then OK.
View > New Guide, check Horizontal and enter 21, click OK.
View > New Guide, check Horizontal and enter 31.5 then OK.
Now do View > New Guide, check Vertical and enter 8 and click OK.
View > New Guide, check Vertical and enter 16 and click OK.

There, now the image is divided up into chunks my printer can handle.
Select the Marquee tool and, with Snap To > Guides enabled, select each section and copy it to a new image then print it.

Note I haven't actually tried this yet as I'm not done with my poster but I think it should work. Oh, and don't forget to flatten your image first too!