PDA

View Full Version : How do I set resolutions to get good results in print?



smyrin
03-09-2010, 09:01 AM
So I have been working on a world map for a D&D campaign and I thought that I would test print a small section to see how it would look. I was a little disappointed with the result and have a few questions for anyone that can help.

The original file is done is Photoshop with a 300 dpi setting. I converted it to a jpeg and then cut out a 7 in x 9 in slice for printing. Needless to say when I printed the image, I seemed smaller (maybe by twice as much) on paper than if I were to view it in Windows Photo Gallery. In another words, what I am seeing on the monitor is so much better than what I have printed.

Should I have it professionally printed? Should I have it enlarged? What am I not getting between monitor and printer resolutions?

Thanks for any advice.

torstan
03-09-2010, 11:05 AM
Your monitor is about 100dpi and your printer is 300dpi. So your printed image will be 3 times smaller than it looks on the screen at 100% zoom (same amount of pixels crammed into a smaller space). If you want to print it out at the size you see it on the screen you'll need to set the resolution of the jpg to be 100dpi and print that.

ZleapingBear
03-09-2010, 11:41 AM
another thing... your map is quiet color full. migth want to think about spending money on photopaper with a special surface. it costs more then the usual. but the result is more close to what you seen on the screen (glosy for ligth) do, it will lose any feal of "old" you migth want to keep.

bartmoss
03-09-2010, 01:20 PM
Here's a little trick: I recently needed to print a birthday card - fast, and in color. So I went to the nearest photo store, and had them print it in A5 size. Cost me <1€ and came out great. They can also do larger maps, and the prices were quite reasonable. You might want to check into that. I have absolutely no idea how it'll look for your map, but if it costs a few euros for a4 size or so, it might just be worth the experiment. Of course, as the leabing bear says, it won't feel like an "old" map then.

Midgardsormr
03-09-2010, 04:43 PM
I downloaded your image and opened it in Photoshop—most of its colors are outside of the typical printing gamut. Go to View > Gamut Warning. All of the areas that turn gray in that view are colors that a printer cannot reproduce. Turn that off, and go to Image > Mode > CMYK Color. A warning dialogue will pop up telling you that you're about to change the color profile from sRGB to, probably, U.S. Web Coated. Go ahead and hit "OK." You'll see the colors immediately change, moving into a printer-safe gamut. If you go back to the gamut warning, you will see that none of the image goes gray any more.

In order to get those luminous greens, you would probably have to do a lot of experimenting with different papers and a very expensive printer, the sort that professional photographers use. Even then, you'll never get quite that bright a color, I don't think.

One other thing to think about is that it is nearly impossible to set up a monitor to represent colors exactly as they will print unless you have use a calibration device to profile both your monitor and your printer. You can get pretty close, though. Monitor calibration and gamma (http://www.normankoren.com/makingfineprints1A.html).

smyrin
03-20-2010, 07:57 AM
Thanks for all the advice. I took the file to Kinko's to test print on regular paper and they did a fantastic job at only a couple bucks (on 11x17). I had then test print at 150% and 200% and they both turned out very well and true to color. Now I know the final print will turn out well. Thanks again.

Carnifex
03-27-2010, 12:15 PM
It's (quite) easy to check the print size.
Here's a little mini-guide to scaling things in Photoshop that might help you:

If you want to change only the dpi (to 300 dpi) but keep the pixel size:
Image > Image Size (or alt+ctrl+I)
Make sure "Scale styles" and "constrain proportions" are checked. "Resample image" should NOT be checked.
Type "300" in the resolution box.
You now see the correct print size!
Click OK.


If you want to scale the image and increase pixel size:
Image > Image Size (or alt+ctrl+I)
Make sure "Scale styles", "constrain proportions" AND "Resample image" are checked.
Type the new pixel size click OK.
(Be careful when you increase the number of pixels of a picture - you'll always loose quality.)

Does it make sense?

smyrin
03-30-2010, 04:55 AM
Thanks for your input Carnifex but I did not need to chage the resolution of the project (already at 300). My issue was that the display I was so used to seeing on the monitor was not what I was getting at print time, something I assumed would be the case. Any hoot, thanks for the advice.

tilt
03-30-2010, 09:51 AM
just to be sure you understand what you have to look for :)
the dpi should be at least 150 for print and 300 for press (you got that)
the document size will then reflect how big the print will be
the pixels are how many pixels are in the picture = they are connected to dpi and document size, so if you raise the dpi but keep the document size, the number of pixels will increase, if you raise the dpi but keep the number of pixels, the document size will decrease :)

smyrin
03-31-2010, 03:55 AM
Nice to hear from a couple fellow Swedes! How's the weather?

tilt
03-31-2010, 03:58 AM
its raining cats and dogs and 6 degrees celcius - so typical spring *lol* ... and I'm actually danish living i sweden so I concider myself an Íresund citizen :)

Carnifex
04-06-2010, 03:47 PM
It's raining. Surprised? :)

Well to the subject again:
Go to Image > Image size...
If the resolution is set to 300 dpi you can easily see the document size right in that window (just above "Resolution"). Of course the actual printing size can be changed if you use the image in another program (like Adobe InDesign).

(about what Tilt said but explained in another way)

tilt
04-07-2010, 02:38 AM
you can never explain this in enough ways, its a dfficult subject for most :) ... until of course they get it.. then its... "ah.. NOW I see, thats easy :)"

Hai-Etlik
04-11-2010, 08:06 AM
you can never explain this in enough ways, its a dfficult subject for most :) ... until of course they get it.. then its... "ah.. NOW I see, thats easy :)"

Yep, the problem is most people just can't wrap their heads around how simple it is, they try to find some complexity that isn't there and get confused when they can't find it.

I think what might be the problem in this case is that even though there's a bit of metadata that says "display at 300dpi", when it's displayed on the screen, that is being ignored and it is being displayed at the native resolution of the screen.

In The GIMP, open the View menu and turn off "Dot for Dot". This will make the GIMP resample the image on the fly so it will appear at the right size. There should be a similar option in other raster image editing software. (This won't touch the underlying image data, it just changes how it's displayed)

Midgardsormr
04-11-2010, 11:19 AM
It also doesn't help that we continue to hear phrases like "The resolution of the Internet is 72." That is a direct quote from a web design teacher at my university; I almost threw something at him. Then I calculated the total number of public addresses in IPv4 and divided it by the land area of the planet to learn that the actual resolution of the Internet is about 26. Of course, that's going to be thrown off somewhat by satellites and ocean-based nodes, so I have no idea how close the number actually is.

Incidentally, the printed size of the image will still likely be different because Gimp doesn't know how large your screen is. It will probably assume 72 ppi, but that is only going to be correct a fraction of the time. My screen, for instance, is 19" wide and displaying full HD (1920 horizontal pixels), so it's a little more than 101 ppi, which means that when I hit the "Actual size" button in Photoshop (yet another misnomer) the image I see is quite a bit smaller than it would print. My HDTV, on the other hand, is 23.5" wide but only 720p (1280 horizontal pixels*), so its resolution is a mere 54 ppi.

Since we're offering additional new explanations, I thought I'd point out the "word math" involved here. "Per" means division, so "Dots per inch" is equivalent to dots (pixels) divided by inches. dpi = pixel / inches. Now you can use algebra to rearrange the equation to solve for whichever piece you're missing.

Want to know the resolution you need to print a 2000 x 3000 image in an area of 8" x 10.5"? dpi[w] = 2000 / 8 = 250 and dpi[h] = 3000 / 10.5 = 286
In order to fit the image in the vertical direction, you need 286 dpi. You have to use the bigger of the two numbers to avoid the image being cropped on the other sides.

Need to know how to set up your document to print at 300 dpi in an area of 10.5" x 16.5"? 300 = pixels / 10.5 and 300 = pixels / 16.5. Rearrange to pixels = 300 * 10.5 = 3150 and pixels = 300 * 16.5 = 4950.
The pixel dimensions of your document need to be 3150 x 4950.

How big a piece of paper do you need to print your 6000 x 4000 image at 200 dpi? 200 = 6000 / inches and 200 = 4000 / inches. Rearrange to inches = 6000 / 200 = 30 and inches = 4000 / 200 = 20.
You will have a poster print at 30" x 20".

dpi = dots / inches


--------
*That's not really accurate, since my TV doesn't use square pixels, but that's a completely different topic that I won't go into here. It's close enough for government work.

Hai-Etlik
04-17-2010, 08:04 PM
Incidentally, the printed size of the image will still likely be different because Gimp doesn't know how large your screen is.

Yes it does actually, at least if the OS/Windowing system knows and reports it accurately.

Jaxilon
04-17-2010, 08:15 PM
Asking it another way - As long as my dpi on my Gimp image is different than the dpi on my printer then it will print a different size?

Personally, I have my dpi in Gimp at 300 but my printer can do 300dpi or 600dpi - I'm going to go experiment with this now. I wanted to print something at 3" x 5" but it came out about 75% smaller...I'm thinking because I was 300dpi and 600dpi.

Bah - changing my printer to 300dpi doesn't seem to have changed anything. When I look at my "image properties" it shows 100 x 100 ppi <--- I know it means pixels per inch but I don't know if that is the same as dots. I guess Pixels is screen and dots is printer...so if I create my image at 600ppi would that print out correctly on my laser at 600dpi? I've almost given up on getting a 3x5 printout because I can't seem to get this.

What's killing me really is that I attempted to create a create a new template in Gimp for a 5x3 inch card but I seem to have failed utterly to have set it up right. I don't really care what it looks like on the screen but I need it to print at 5x3 inches.

Meridius
04-17-2010, 09:23 PM
dpi = dots per inch

How big is your file in pixels?
Divide the number of pixels by the number of inches you want the print to be. That will be the DPI at which you'll have to print. DPI on computer screens is an 'empty' word.

Let's say your file is 1500 by 2500 pixels. 1500 pixels divided by 3 inches = 500 dots (pixels) per inch. 2500 pixels divided by 5 inches = also 500 dots (pixels) per inch.

Let's say you want a 300 dpi print in 3" by 5". That's 3 inches times 300 dots (pixels) per inch = 900 pixels. Also 5 inches times 300 dots (pixels) = 1500 pixels. So if you want to print at that size at 300 dpi, your file needs to be AT LEAST 900 by 1500 pixels.

It's just that stupid programs like GIMP and Photoshop decide how big an inch is on your screen, which probably isn't true to reality.

When starting to make a map, it's important to decide on what DPI and what size you'll want to print your map. Because the size times the chosen DPI will be your minimum resolution. So let's say you want to print a map at a large size 12" by 18"... at 300 dpi printing that's a whopping 3600 by 5400 pixel file (in digital camera terms that would be a 19,44 megapixel image). That's why deciding your print size before making your map is important... because my computer will die a thousand painful deaths if I attempt something as big as that. I wanted a map of about that size (glue and a poster-print setting can make A4's into A2's real easy), but decided to go with 150 dpi, it's more than sharp enough. People won't be going over it with a spotlight and magnifying glass, so you can easily get away with 150 dpi. 12" by 18" at 150 dpi gives a much more 'managable' 1800 by 2700 pixel image (only 4,86 megapixels). Now I went slightly over my design specs, and ended up with 2000 by 3000 pixel file (and my computer still had a hard time, but at least it hasn't blown up in a spectacular fireball).

Jaxilon
04-17-2010, 09:40 PM
dpi = dots per inch
When starting to make a map, it's important to decide on what DPI and what size you'll want to print your map. Because the size times the chosen DPI will be your minimum resolution. So let's say you want to print a map at a large size 12" by 18"... at 300 dpi printing that's a whopping 3600 by 5400 pixel file (in digital camera terms that would be a 19,44 megapixel image). That's why deciding your print size before making your map is important... because my computer will die a thousand painful deaths if I attempt something as big as that. I wanted a map of about that size (glue and a poster-print setting can make A4's into A2's real easy), but decided to go with 150 dpi, it's more than sharp enough. People won't be going over it with a spotlight and magnifying glass, so you can easily get away with 150 dpi. 12" by 18" at 150 dpi gives a much more 'managable' 1800 by 2700 pixel image (only 4,86 megapixels). Now I went slightly over my design specs, and ended up with 2000 by 3000 pixel file (and my computer still had a hard time, but at least it hasn't blown up in a spectacular fireball).

This would be good to have in our FAQ or beginner's guide because I'm only now starting to get it but it's a question I came here with. I haven't tried to print any of my maps yet but I can foresee all sorts of headache if I tried with what I've made so far. I just ripped a number of pixels out of my head and started making a map. Now I can plan. I will see if I can get this stupid 3x5 card thing to work now using what you just explained. Thanks.

Midgardsormr
04-18-2010, 10:35 AM
Yes it does actually, at least if the OS/Windowing system knows and reports it accurately.

Truly? I did not know that. In any case, though, I can't speak for every system (and not for Gimp at all, since I use PS), but I have seen no indication that my OS has ever known the physical dimensions of my screen. I currently have a very new full HD monitor connected via DVI, and although Windows has a lot of information about it, physical size does not seem to be one of those. Further, Photoshop has no apparent switch to enable it to take such data. You can, however, set the default screen resolution manually through Edit > Preferences > Units and Rulers.

smyrin
04-18-2010, 02:04 PM
When starting to make a map, it's important to decide on what DPI and what size you'll want to print your map. Because the size times the chosen DPI will be your minimum resolution. So let's say you want to print a map at a large size 12" by 18"... at 300 dpi printing that's a whopping 3600 by 5400 pixel file (in digital camera terms that would be a 19,44 megapixel image). That's why deciding your print size before making your map is important... because my computer will die a thousand painful deaths if I attempt something as big as that.

This is why I started this thread! I engaged a huge project on my PC cause I wanted to develop a world that I could have professionally printed. I read a few posts and it was suggested that I create the project at a 300 dpi resolution so that it would print well. So I started a Photoshop file at size 7200 x 7200 pixels and 300 dpi (24 square inches). My laptop can handle the file size and even the hundreds of layes (just takes 5 min to save it!). I thought I was setting this up correctly but after trying to test print it, I was confused about how the final was going to appear. I noticed that when I print on my home printer, I get a smaller version of what I was seeing on the screen and the quality was terrible. I test printed at Kinko's (pro) at 150% and 200% and they started looking good. This is all very confusing. I naturally assumed what I was seeing on the screen in PS7 was what I was going to get in output. This is not the case and I cannot figure out why there is a difference or what the quantative change is. I don't think it has anything to do with how I set up the file. The digital display of the image and the acutal print output just do not match in size ratio. I am beginning to think that the digital display is enlarging the image by 20-50% and the print output is in its correct size specified by the file.

Meridius
04-19-2010, 11:01 AM
Hmm, I'll do a bit of math with my own monitor. As I do not know the physical dimensions of yours.

My monitor displays at 1280*1024 (it's almost square). For the sake of simplicity, I'll just take the width of the screen, since the height will (AND SHOULD!!) yield the same number anyway. It's 1280 pixels WIDE, and if I grab my tape-measure (which luckily also has inches on it, so I don't have to convert cm to inches), my screen is 'about' 15 inches wide. So 1280 pixels, divided by 15 inches, is 85,333... So the DPI of my screen is just over 85.

Let's do the math, your file is 7200 pixels by 7200 pixels. So on MY monitor your full res map would be just under 85 inches by 85 inches... (so I'd see only a small portion at a time of your map. Now, the more pixels per inch, the smaller your image gets. Because those 7200 pixels are a CONSTANT. If you raise the dpi, the physical size of the image in inches will be smaller. If you lower the dpi, the size will increase. But also remember that dpi also measures the amount of detail per inch.

I don't know how the 'quality' of your print ended up wrong, but this can have several causes:
1: Your colours are 'out of gamut'. Your monitor can show colours your printer cannot show. This only applies if the colours looked wrong.
2: Your printer is not fit for this job. This is unlikely, since I have a cheap multifunction printer myself, and it prints fine.
3: You have detail in your map which starts to look bad if it is compressed into a high DPI, this is quite likely, since you say that the large test-prints at the professional print-shop turned out 'reasonable'. 7200 pixels printed at 150 dpi is in fact the same result as printing your 300 dpi image 'on 200%'.

So, look up the current resolution of your monitor.
Grab a tape-measure, and physically MEASURE your monitor.
Divide the number of pixels by the number of inches. That is the dpi of your monitor. If you want your print at the exact same size. Print at that dpi, but be warned, paper doesn't tolerate 'low' dpi's as well as monitors do. Your monitors dpi is probably around 3 times as low as the dpi you're asking from your printer. Which also means the image on screen appears 3 times bigger than on paper.

I find that for gaming purposes, usually in rooms which have been lit 'satisfactory' and people just admiring the map from about 30-60 cm away (1-2 feet), 150 dpi is fine. 300 dpi is REALLY high quality, but I doubt people would see the difference without an actual side-by-side comparison.

Try to keep print and screen separate in your mind. If it helps, you can also activate the on-screen rulers in GIMP or Photoshop. This way you can get a good feel for the size of the PRINT.

Midgardsormr
04-19-2010, 11:08 AM
First, printing a full color image at home on normal paper is very likely going to result in terrible quality. Ordinary copy paper will quickly be saturated by a 300 dpi print, and the ink will run, resulting in blurriness. Even high quality paper is unpredictable, and it takes some experimenting to develop a printing profile for a particular stock.

Now, as for the discrepancy between the screen size and the printout size, try the following steps:

Obtain the current horizontal screen resolution of your monitor. Under Windows, go to the Display Settings and look at "Resolution." The first number is the one you want.

Measure the physical width of your display—just the actual screen, not the frame. Divide the horizontal resolution by your screen's width. That is the actual ppi (pixels per inch) of your display.

Now, in Photoshop, go to Edit > Preferences > Units & Rulers and change the screen resolution to your actual ppi. The default is 72, which is almost certainly wrong.

Click once on the Zoom tool, and in the bar at the top, click the button that says "Print Size." Make sure your rulers are displayed (Ctrl-R if they're not), right-click a ruler and choose "inches."

Get out your physical ruler again and compare Photoshop's ruler to your own to be sure they're the same. If they are, then you know that whenever you are in this zoom mode—Print Size—the size of the print should be the same as what appears on your screen.

However, you may need to explicitly tell the printer driver not to scale the print, because that's just going to throw things off again.

I recommend that you do not work exclusively in the Print Size mode because you never know which pixels Photoshop is throwing away in order to show you that resized image. It's a good idea to reference the image frequently at both full resolution (Actual Pixels), and in Fit Screen mode, where you can see the entire image and know what it will look like from a distance.

Note that some of the buttons and menus may be a little bit different in PS7—I'm using CS4.

Hai-Etlik
04-19-2010, 10:49 PM
Truly? I did not know that. In any case, though, I can't speak for every system (and not for Gimp at all, since I use PS), but I have seen no indication that my OS has ever known the physical dimensions of my screen. I currently have a very new full HD monitor connected via DVI, and although Windows has a lot of information about it, physical size does not seem to be one of those. Further, Photoshop has no apparent switch to enable it to take such data. You can, however, set the default screen resolution manually through Edit > Preferences > Units and Rulers.

Well I don't know about Windows, but X.org on Ubuntu has no problem with this. I can use xdpyinfo to bring up all the information about my display and dimensions and resolution are right there.


screen #0:
dimensions: 1280x1024 pixels (339x271 millimeters)
resolution: 96x96 dots per inch

It's a rather old monitor, it doesn't even have a DVI input.