View Full Version : Dumb question about resolution and photoshop views

11-20-2004, 12:40 AM
The answer to this is probably obvious, but I get totally confused. The question: if computer screens have a resolution of 72 ppi (roughly), can you preview what it will look like printed at 300 dpi? Can you preview a higher resolution (300 dpi printed) than what you're viewing the preview on (the monitor, 72 ppi)?

Related to this (I think) is a question about Photoshop viewing options. What do "actual pixels" or "print size" mean? And when you're viewing something at 100% or 50%, percent of what? What is the "real" size of a digital image?

11-20-2004, 05:04 PM
Hi, I have been using photoshop for many years without any formal education, so I hope I can help. There isn't a real way to view higher than 72 ppi, but I have found that you can judge the quality somewhat by going to the navigator and making the image really large. The higher the ppi, the less pixellation you will see. I used to print a sample just to be sure, but after many samples I trust that my images will print good at 300 ppi. To see the image size in inches or pixels, you can go to Image/Image size. I really hope this helps.

11-20-2004, 07:39 PM
Thanks CLB, that was helpful.

But I have a dumb follow-up question now.

If you are planning to do large scale print work, how do you set it up in Photoshop (or other programs)? I'm thinking of someone like Barbara Kruger. I'm not sure whether her work is digital, but it could be - and the prints are large - 60x40", or some things look like they cover an entire wall.

Do you set up your Photoshop document to be 60x40" and 300 dpi? I would think this would eat up all the power of most computers, especially if the image is complicated, has lots of layers, etc.

Or do you work at a smaller scale and just have a sense (from experience perhaps) about how it will look when enlarged and printed?

11-21-2004, 12:48 AM
You might get more specific, expert information, and some reassurance by talking to a few print shops, ones that do large format printing.

Describe your image, what kind of detail is required, how far from the viewer it will be displayed, on what kind of material you want it to be printed, and any other information that will help them understand what you're after when the image is printed.

If the image will be seen up close and contains areas of fine detail, you may need to use a higher PPI number (and not blow the image up larger than its original dimensions).

If the image is, for instance, a watercolor painting which would be typically softer with no sharp detail, you may be able to get away with a lower PPI number for the final print (or blow the image up larger than its original dimensions).

If the image is to be printed on canvas (I've read), that you may be able to get away with a lower PPI number for the final print (or blow the image up larger than its original dimensions) since some detail is lost anyway when printing on the canvas' rougher surface.

If the image is to be displayed many feet from the viewer, again you may be able to get away with a lower PPI number for the final print (or blow the image up larger than its original dimensions).

If you're using Corel Painter, you won't be able to work at such large dimensions in images for a couple of reasons:

Painter has a limit of about 54 inches at 300 ppi. (This does not mean the image can't be enlarged for printing and still retain good quality... depending on the image, how it will be seen, on what surface it will be printed, etc.)

Large image dimensions at 300 ppi, even smaller than what you describe, slow down Painter's performance and seem to be one cause of the software crashing. This is especially true when the image contains multiple Layers.

From what I read on some of the message boards, this is also a problem with Photoshop CS, though I am a very light Photoshop user and only have Photoshop 7, so I can't speak from personal experience here.

Some artists get around the large image/slow performance problem by working in three stages. Working backwards from the final image dimensions, and using an example final image at 3000 x 3000, 300 ppi, below is a for instance scenario.

First stage - Block in large areas of color on an image that's:

1000 x 1000 pixels at 75 ppi

Second stage - Add large details after resizing the image to:

2000 x 2000 pixels at 150 ppi

Third stage - Add fine details and clean up the image after resizing the image again to:

3000 x 3000 pixels at 300 ppi

This three stage method allows you to use smaller brush sizes at each stage and should also cut down on the demand on system resources as you should be able to collapse/merge Layers along the way.

Again, talk to several print shops until you feel you've learned enough and heard enough views to feel confident proceeding with your work.

Best wishes!

11-21-2004, 03:56 PM
Thanks Jin. Your post helped me see what my real problem is - namely, I'm not sure what size I might want to print at. I'm new to doing digital work, and right now I'm really just experimenting. So many of the things you said to consider - which all sounded reasonable - aren't really what I'm thinking about because I'm not at that stage of the game yet.

I guess I really have two concerns. First, is there a way to preview what a printed piece will look like (sort of, but not really - if I can paraphrase CLB)?

Second, if you're working on something that might end up being printed, but you're not sure yet, and if it is printed, you're not really sure what size would be best (eg, because the work you're doing is experimental), then is there a "best" way to set up the image settings (pixel dimension, resolution, linear dimensions)? For example, would working at 8.5x11 and 300 dpi be reasonable flexible if I might want to shrink it by 50% or increase it by 300%?

Doing some more research on the Web, it sounds like increasing size might not be as problematic as I first thought. Apparently, professional shops have interpolation software that is better than what Photoshop offers, and they have ways of blowing things up so that they look pretty good. And I doubt that any of my experiments will need to be super-sharp when printed large.

I guess another way of putting this is this... I'm worried that I'm going to make something I like, but then find out I didn't set it up right, and it can't be printed or looks bad when it's printed.

11-21-2004, 06:30 PM
Hi bigblackbox,

Again, talk to some print shops... several.. to get several points of view. When the info they give you begins to "collect" in a pile (they begin to say the same things enough), that might help you decide how to approach your experimental work.

There's no other way I know of to preview the print except to do a test print. Otherwise, you're limited to what can be displayed on the screen and also what colors look like on your partictular screen which would look different on any other screen and also different when printed (to one degree or another).

The experts at the print shops will be able to give you more tips than we can since they deal with this all the time.

Bottom line, though, you're going to have to plunge in and see what happens in real life printing but I would not do that before talking with the print shops on the chance you do find something you like a lot among your experiments. That will not guarantee the print will be nice but it'll improve the chances for a successful outcome.

To begin with, you might try doing some test painting using a few different painting styles and brush variants on a medium sizedl Canvas at 300 ppi, have it printed at several reductions/enlargements, and at 100% and see how it looks. This would not be a work of art, just a sample.