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Thread: 300 dpi
02-10-2011, 02:14 PM #1
I need to submit some photos that are in jpeg format with a 300 dpi resolution. I have the jpeg format down. I just switch my camera to that setting.
Getting the solution to 300 dpi is a complete mystery to me. I have downloaded picasa3 in hopes of being able to save the image to 300 dpi resolution but can not figure out how to do this. I also have windows vista home premium. Really do not want to spend anymore money on software since the camera was expensive enough.
Any ideas on how to do this? I have my camera set at the highest resolution possible when taking pictures.
- 02-10-2011, 03:24 PM #2
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DPI (dots per inch) is a printer setting. It's nothing you can do with a camera. They might as well ask you for an image that weighs 2 ounces.
Perhaps they mean 'pixels' per inch, or PPI? 300PPI is a pretty high resolution for images, it gives a very good quality image.
02-10-2011, 05:33 PM #3
Photo Programs usually you can change the image to 300 or higher, scanning an image you can also tell the scanner at what resolution to scan.
I know in paint shop pro (which is like $100) you can tell what resolution you want an image at. When people sell images online for scrapbooking etc they are usually at 300
02-10-2011, 06:13 PM #4
This really has me confused. I think the software I currently have it is not self explanatory. I even read a site where it was stated that it has to do with printing which is really on there end. Also that anything higher than 12 megapixels for a camera that it really is just redundant and any picture would be above 300 dpi. So I am completely confused and figure I will just submit the pictures using my 14 megapixel camera and keep my fingers crossed.
02-10-2011, 07:15 PM #5
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It can be rather confusing. Here is how to make a jpeg with photoshop: Other wise Gimp is free, I love it and works great. I do some graphic work and love Gimp in Linux so much better then Adobe Photoshop.
Let me know if you have other questions hope this helps. If you have no photo editing then go get gimp it is free. GIMP - The GNU Image Manipulation Program
How to make a 300dpi file;
If you open your file in Photoshop and then use the short cut Alt+Ctrl+I (or on the menu bar Image>ImageSize) you will bring up the Image Size dialogue for the selected open image file. At the bottom unclick "Resample Image". With this setting you can change the size and resolution without damaging the file. Notice that changing one setting makes the others change as well in proportion. Setting the resolution on 300 (or 225, or 350, as you please) you can see the largest size that file can be reproduced in it's current form. If the resulting dimensions are too small you have the option of reclicking the "resample image" box and making the image any size and resolution you want. Be sure to consider the different upscaling processes at the bottom of the box as each affects different qualities of the image. "Rezzing" up the image will not improve the quality and you may find that if you start with a fairly small image and enlarge it significantly it will look rather poor; either fuzzy, blurry or even pixilated. In many cases you can enlarge a file by up to 50% without a serious downgrade in quality depending on the content and quality of the original file.
So what about the 300dpi Jpeg? In an application that uses a 300ppi image we would probably prefer to use a TIFF format file instead of a JPeg. As you will see why, with just a few exceptions (see below) you would not use a "300dpi JPeg".
Found this to be the best explanation. You can find more information on here at : What is a 300dpi JPeg?
File Formats - Compression
JPeg is a file format in which what would otherwise be a fairly large file is made much, much smaller by compression. The compression process used by the JPeg format analyses the pixels surrounding each pixel and acquires enough information to recreate the image with only a fraction of the information. This is called "Lossy Compression" and literally throws away a certain amount of the data resulting in a pretty good looking image which may be slightly blurry or have what are called compression artifacts. Some programs allow the user to control this compression so an appropriate balance can be made between damage to the image and the desired file size.
JPeg files are most typically displayed in low resolution on Televisions or Computer Monitors. These displays typically present an image at only 72ppi. They use illumination elements to create color using 3 filtered colors; Red, Blue & Green (RGB). When all three colors are combined together they make White, this is call Additive Color, in contrast to printed color (CMYK) which if all are combined ideally make Black. CMYK makes white on a white surface by applying no ink or color and is there fore referred to as Subtractive Color.
The JPeg format is ideal for display on screens in the content of Websites, PowerPoint presentations and the like because it produces suitable files that are easy to view on computers, are vivid in color and are relatively small due to their compression.
When a JPeg is used for ink printing, particularly high quality printing (high line screen) the damage caused by compression quickly becomes apparent. The image may need to be enlarged if it was originally only 72ppi resulting in a grossly pixilated image when printed in a magazine as you may occasional see when advertisers supply their photos or logos from web sources. A 300dpi version of the file may seem to be the answer, but the JPeg format is not the ideal format for this type of application.
TIFF is an image format which can, but does not always use compression. When compressed it is not like the destructive form used in JPeg. The standard compression format of a TIFF file is not "lossy". The TIFF compression scheme (most commonly LZW, named for the inventors Lempel, Ziv & Welch) finds all duplicate elements in the file and replaces them with an indication of multiples. In effect in stead of having 000000000 it is replaced with 0x9. This means that no information is lost and the process is referred to as "lossless compression". This allows users to modestly compress an image file without damaging it. However the process of compressing and uncompressing files does take time and computer power and as such many printers and publishers prefer "uncompressed TIFF" format.
02-11-2011, 11:07 AM #6
Thanks for the information. I do not have photoshop. I do not plan on purchasing it right now since it is expensive. I do have picassa. I can look in Gimp. It would be great to have directions to do this in Gimp since I do not have photoshop.
02-11-2011, 11:14 AM #7
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Here is some information on how to save in Gimp:
Saving Images as JPEGs in GIMP - How to Save a JPEG in GIMP
[ame=http://www.youtube.com/watch?v=3EFOmSK5iXA&feature=related]YouTube - Saving an image as a jpg in GIMP[/ame]
02-11-2011, 12:12 PM #8
Thanks for the information. My camera lets me set it to take a jpeg. That is not a problem. What I am confused about is the requirement for "image resolution must be set at 300 dpi". I do not have photoshop nor do I plan on purchasing it. I do have picassa and I also have windows photo gallery. When I go into the information on the image it states in one photo the vertical image resolution is 180 and the horizontal image resolution is 180.
Is this the same as having an image resolution of 300 dpi?
02-11-2011, 06:26 PM #9
I just downloaded MSN photo software. It seems to have a function to set the resolution to 300 dpi. Thanks everyone for the help. Great thing is that I did not have to purchase anything!
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