Adobe Photoshop :: Can you increase DPI?


	Can you increase DPI? I need some photos for a press kit. The recommendation is at least 640 x 480 with 300 DPI. The pics I have are 72 DPI. I know, that is really really low, but I didn't oversee them being taken. Wish I had. I know this is a dumb question, but is there a way to increase the DPI? Thx Ignoring any value for resolution, what are your pictures' measurements in raw pixel dimensions? Sounds like you need some foundation in the way resolution works. Go the following link. Scroll down to the "* Start" section. <http://www.scantips.com> -----------------------------------------------Reply----------------------------------------------- To expand, how do you know that is really low? Are they 640 x 480? Is this for print or screen (or web)? If you change them in Image Size to 300 ppi iwith Resampling UNchecked, they will still be 640 x 480. Is that what you want? -----------------------------------------------Reply----------------------------------------------- Sorry guys. I didn't realize I was leaving out a lot of details. The pics in question are 640 x 480 at 72 DPI. They are for an Electronic Press Kit. They ask for 300 DPI so they can have good quality files they can print out. I was told 72 dpi was low. The guy that told me is in school for graphic design, so I assumed he was correct. Yes, I do need a crash course in how all this works. Thanks for the link, much appreciated. Thanks Ed. I think/hope that will work. All I know is they want pics at least 640 x 480 at 300 DPI for print if they deemed necessary. They will also use the pics for brochures, program guides, newspapers and such.... if I am to be so lucky. Thanks again guys! -----------------------------------------------Reply----------------------------------------------- All I know is they want pics at least 640 x 480 at 300 DPI for print if they deemed necessary They either communicated the message to you incorrectly or they have no idea what they are doing. Ask them to clarify. If they define 640 x 480, they don't need to specify DPI. If they specify 300 DPI, they must also specify what physical size in inches that they want. -----------------------------------------------Reply----------------------------------------------- If that's big enough, good. Seems kinda small to me. 72 dpi IS low, for print. You can change resolution but you can't change the number of pixels without dire consequences. 640 x 480 (pixels, right?) is 640 x 480 regardless of the dpi value. If 640 x 480 at 300 is acceptable you should be okay. Remember, Resampling OFF. -----------------------------------------------Reply----------------------------------------------- Kugar, Firstly, let's swap "DPI" for "PPI"...the former is more of a printing lingo for "dots per inch", where the resolution of a digital image is measured in PPI, "pixels per inch". As Ed said, a 640x480-pixel image at 300ppi will print out as a 640/300 x 480/300 size file in inches, or 2.1x1.6 inches. So, just tell them to print at that size, and you're covered! ha! Seriously though, the question becomes one of what size do they need an image to be printed at? If double the size is all, as roughly a 4x3-inch image, then you may well be able to resample your image to 1280x960-pixels and have something of passable print quality at 300ppi, but I doubt it. More than that? I don't know the limits, but you will find the image quality degrades more and more as you resample to larger pixel dimensions. Even this example I quoted is, in essence, 75% artifically created data, 25% original data. That's not exactly true but is an easy way to understand why the image quality would suffer. Hmmm..."they want pics at least 640x480 at 300 DPI". If that is exactly the specification they gave you, then you can easily leave resampling off (unchecked) and set the resolution to 300ppi in the Image Size dialog. That really will change nothing about the image but, when saved, it will update information in the EXIF data for the file. Really, all they would have needed to tell you is they need images no smaller than 640x480 pixels, because it is up to the person doing the printing to ensure the application handling the image for print is treating it as a 300ppi resolution image. After all, for some brochures and such, a 2.1x1.6-inch image may truly be "big enough" depending upon the context of its use. Regards, Daryl -----------------------------------------------Reply----------------------------------------------- <Kuga@adobeforums.com> wrote in message news:3bc41177.2@webcrossing.la2eafNXanI... - Hide quoted text - > Sorry guys. I didn't realize I was leaving out a lot of details. > The pics in question are 640 x 480 at 72 DPI. They are for an Electronic > Press Kit. They ask for 300 DPI so they can have good quality files they > can print out. > I was told 72 dpi was low. The guy that told me is in school for graphic > design, so I assumed he was correct. > Yes, I do need a crash course in how all this works. Thanks for the link, > much appreciated. > Thanks Ed. I think/hope that will work. All I know is they want pics at > least 640 x 480 at 300 DPI for print if they deemed necessary. They will > also use the pics for brochures, program guides, newspapers and such.... > if I am to be so lucky. > Thanks again guys! What you have is a file which is 640 x 480 pixels. What you told PS to do is to display this file at 72 dpi. Hence, the display will be (about) 9 x 7 inches. What they appear to want is a file which is 640 x 480 pixels. It looks like they want to display the file at 300 dpi. If so, then the display will be (about) 2.13 by 1.6 inches. The only way to make the displayed image bigger is to add many more pixels. Of course, that can be done using one of many tools (bicubic interpolation for example). However, the end result tends to be way less than good. Jim -----------------------------------------------Reply----------------------------------------------- The pics in question are 640 x 480 at 72 DPI. Are your images actually 640x480? The resolution measured as ppi -- and note that dpi is not the proper terminology -- combined with the pixel dimensions determine the print size. ppi is irrelevant for images viewed on a monitor with pixel dimensions determining the viewing size. As noted above a 640x480 image at 300 ppi is a very small image when printed. -----------------------------------------------Reply----------------------------------------------- On Sat, 2 Jun 2007 19:03:47 -0700, Kuga@adobeforums.com wrote: >Sorry guys. I didn't realize I was leaving out a lot of details. >The pics in question are 640 x 480 at 72 DPI. They are for an Electronic Press Kit. They ask for 300 DPI so they can have good quality files they can print out. >I was told 72 dpi was low. The guy that told me is in school for graphic design, so I assumed he was correct. >Yes, I do need a crash course in how all this works. Thanks for the link, much appreciated. >Thanks Ed. I think/hope that will work. All I know is they want pics at least 640 x 480 at 300 DPI for print if they deemed necessary. They will also use the pics for brochures, program guides, newspapers and such.... if I am to be so lucky. >Thanks again guys! The simple answer is that being only 72 dpi at 640 x 480, when you change the resolution to 300 dpi, the actual size of the image is 2.1x1.6 inches, as the others have said. If that size is too small and you need to make it bigger, but still keep the 300 dpi, then the software has to interpolate the extra pixels needed to make the picture larger. When you create extra pixels, the image suffers and looks pretty bad, depending on how many pixels you need to add. If you only want to increase the size slightly, you can get away with it, but even just doubling the size to 4.2x3.2 inches will result in a poor picture. Sorry, but in essence, the answer to your question is no, if you want to maintain the same size, increase the dpi and keep the same quality. Talker -----------------------------------------------Reply----------------------------------------------- Thanks again guys for the info. It is impressive to see how knowlegeable and helpful everyone here is! It's obvious I have a lot to learn and you guys are doing a great job of teaching me the ropes. I had a photographer take some 35mm pics for the film. They were physically 6 x 4. She also gave me a disc with digital prints of the pics. The digital versions are 640 x 480. I am thinking about submitting some screenshots instead. They are 720 x 480 (widescreen). I assume those would be better, well wider. Other than that I don't have much to go on in terms of available pictures to submit. They want pics that they can use in a variety of formats; print, web, newspaper, brochures, program guide, etc. "IF" I get so lucky... BTW Can you take pics larger than 640 x 480 with consumer digital cameras? I wasn't aware you could. Thanks again guys! -----------------------------------------------Reply----------------------------------------------- 640 x 480 is nowhere near large enough for using in brochures. 2x1" is about the most you could expect from a file that size. Don't submit a screen shot. The Repro would be terrible. As a guide, for brochures you would need to be submitting 300 ppi resolution files. By doing the math you would need a 1200 pixel by 900 pixel file to reproduce successfully at 4" x 3". The disc she has given you are "thumbnail" proofs. Ask her for high resolution versions of the scans. As for "consumer" cameras. Yes there are very many available these days which are capable of much higher resolution than 640 x 480. -----------------------------------------------Reply----------------------------------------------- <Kuga@adobeforums.com> wrote in message news:3bc41177.7@webcrossing.la2eafNXanI... - Hide quoted text - > Thanks again guys for the info. It is impressive to see how knowlegeable > and helpful everyone here is! > It's obvious I have a lot to learn and you guys are doing a great job of > teaching me the ropes. > I had a photographer take some 35mm pics for the film. They were > physically 6 x 4. She also gave me a disc with digital prints of the pics. > The digital versions are 640 x 480. > I am thinking about submitting some screenshots instead. They are 720 x > 480 (widescreen). I assume those would be better, well wider. > Other than that I don't have much to go on in terms of available pictures > to submit. > They want pics that they can use in a variety of formats; print, web, > newspaper, brochures, program guide, etc. "IF" I get so lucky... > BTW Can you take pics larger than 640 x 480 with consumer digital cameras? > I wasn't aware you could. > Thanks again guys! You most assuredly can make images bigger than 640 x 480 pixels. In point of fact, you cannot make them that small with any digital camera unless you process them to reduce the pixel count. Jim -----------------------------------------------Reply----------------------------------------------- You may want to check the disk again; sometimes the thumbnails are in the main directory but the higher-resolution images are in a subdirectory. The filenames may be the same as the thumbnails or they may be slightly different, but with the same number (e.g., THM001.jpg vs. IMG001.jpg). -----------------------------------------------Reply----------------------------------------------- BTW Can you take pics larger than 640 x 480 with consumer digital cameras? Yes, with all but the earliest cameras. Most cameras have a megapixel rating, and five and six is now a low number. a 640x480 is 0.3 megapixel, so you can see that the newer cameras are much higher. -----------------------------------------------Reply----------------------------------------------- That's true. The lowest megapixel rating of any camera I've owned was .5 and that was years ago.