Saving at 300dpi

This question might not really belong in this forum but I didn't see a more appropriate place.

I have PhotoImpact 8, a Ulead program. I know it's old but it does the job for me. I also have Microsoft Picture It. Even older.

My problem: When I create a new image in PhotoImpact the options are to set the image size and the resolution. I always set the resolution for 300dpi. When I save it the options are the file type and the choice of no compression, I choose no compression.

In Picture It you set the resolution and compression in the options section.

Last week I uploaded a simple text graphic logo to Vistaprint. When I viewed it on there it obviously wasn't 300dpi, the resolution was poor.

I thought with those options set that my graphics were being saved at 300dpi. Why aren't they and how can I fix this?

Thanks for any help,

Mike

0 Phil1923 over 11 years ago

Hi Onguitar,

   I can’t specifically answer your question since I have no idea what those programs do. However, DPI confusion goes back to prehistoric times. Wars were fought over it.

   I’ll take a simplistic shot at it. You will get much better answers from the professionals in this forum.

1. The image data within the file does not know anything about dpi and physical size. Consider an image at 300 dpi and 4” x 6”. That dpi and size are nowhere to be found on the camera’s CCD. Neither is it a part of the scene.

       So what does the file contain.

2. It contains rows of pixels. If you want to know the true resolution of an image for my 12 MPixel camera then the resolution is one pixel out of 4,000 horizontally and one pixel out of 3,000 vertically. That’s the real resolution. The data in the file can be visualized as a mosaic of 12 million tiles. Each tile has a single color. The picture is created from these pixels (aka tiles) in exactly the same way that a picture can be created from a collection of tiles.

       So what’s with the size descriptions which give dpi and size.

3. For starters, it’s Pixels per Inch (PPI) – not DPI – that concerns us. DPI is left over jargon from offset printing ..

4.   If I want to print a picture, I have to tell the printer what size I want. That’s the size of the print. It’s not the size of anything else.

5. Let’s avoid advanced mathematics. Take an example – my 4,000 x 3,000 pixels shot of the Passaic River.

6.   Let’s try several sizes

         --- The wife wants the long dimension to be 36” to fit a picture frame.

         --- I tell PhotoPaint to make the image 36”. Without so much as asking for my approval, PhotoPaint sets the dpi to 111 dpi.

         --- Before I can ask what the hell is going on, the wife says she wants a 24” print. I set in 24” for the width. Damn. A dpi of 167 pops up. Nobody asked for that dpi.

7.   One of the grandchildren explains it to me. The image is 4,000 pixels (aka dots) long. Divide 4,000 by 36” or 24” and you get the dpi which PhotoPaint offered.

          YOU DON’T HAVE TO ACCEPT THE OFFERED DPI.

    However, in that case you are changing the size in pixels of the file. That may or may not be what you want. It’s another ball game. Most likely, it’s the cause of your problems. Changing both size and dpi will change the resolution of your image.

-----------    I NOW LEAVE A BETTER EXPLANAION TO THE PROFESSIONALS.   --------

Phil
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0 Ariel over 11 years ago

PhotoImpact is a great program, I used it when it was from ULead (I discover it accidentally with the software of one scanner) and later Corel buys ULead, and rename the program as Corel PhotoImpact.

On PhotoImpact you can "save" or "export" (also with he left mouse button) an image, the best choice is to use TIF file format, and choose "file" and "selection" if you want to have a transparent background. CorelDRAW will recognized the selection as an Alpha channel, and the image will be transparent.

The problem of resolution is simple: First of all, you must work at real size, if it's possible, then choose the resolution at 300 dpi. If you have 300 dpi but a small size (on centimeters) the result will be wrong.

"300 dpi" is an information for printing, not for screen. On your monitor you will see a chess board: this is a BITMAP. Each square is a pixel. If you search on Google for a wallpaper for Windows, you will found different resoutions, for example, 1024x768. That means a chess board with "1024 squares" wide. At this point, the size of each square is virtual, in other words, doesn't matter the size of the pixel, the only valid information is the amount of pixels: 1024x768.

But, when you go to print this image, each pixel (each square) must have a size. Then the size of each pixel will be relative to the size of the entre image on centimeters, inches or the units you're using. So, you can enlarge or reduce the entire image, but that doesn't change the amount of pixels. You will have 1024, no matter if the image is big or small. Now when you send to print, the size is important, and the size of each pixel is a big problem. An image with low esolution will have bigger pixels, and an image with high resolution will have small pixels, because in the same size (10 cm for example) will have more pixels.

So, for have "good resolution" you need both: big size and a lot of pixels. If you create an image small (ie 3x2 cm) at 300 dpi if you enlarge it each pixel will be a big square, and the resolution will be poor. If you have an image of 15x10 cm at 300 dpi, probabily you don't need to enlarge it, and you will have a high quality image. Make your image at final size, at 300 dpi and you don't have problems
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0 Phil1923 over 11 years ago in reply to Phil1923

Hi Onguitar,

      Oops.

      I neglected to mention that I routinely check off “maintain original size” in the Resample dialog. That maintains the resolution of one pixel per the length or height in pixels.. That’s the true resolution of the image.

     DPI may be the resolution of the final print on a “per inch” basis. It is not the resolution of the image itself since you can enter any dimensions that you want.

Phil
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0 onguitar over 11 years ago in reply to Phil1923

Phil, thanks. Although this is a little over my head I'm starting to see that my problem wasn't the saving process it was the making of the graphic process.
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0 onguitar over 11 years ago in reply to Ariel

Ariel, after reading all your good information the last paragraph made it clear to me. I was creating my graphic too small. I went back to the program and increased the size of the logo. I uploaded this new version to Vistaprint and previewed the document - looked just right. Thanks so much.

Mike
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