inadequate print resolution?

I don't know what to say this state in English. when data for printing is under 175dpi

midzki said:
I don't know what to say this state in English. when data for printing is under 175dpi

I gave the tag page for inadequate print resolution a description, hopefully it'll help. Also, feel free to check me as I may not have worded it perfectly. (I understand the basic problem, but I'm by no means an expert on it, nor do I scan much stuff so I haven't dealt with it before personally.)

If you shrink it to say 50% does that allow the DPI to increase from 175 to 350?
I don't quite understand how DPI influences printing, since I rarely print.

bakaneko said:
If you shrink it to say 50% does that allow the DPI to increase from 175 to 350?
I don't quite understand how DPI influences printing, since I rarely print.

No, it'll still be 175dpi, but it'll be smaller in dimensions. DPI is largely independent of the dimensions of the image (like 1000 x 1000px = dimensions, but 175 = DPI). Higher DPI translates to more "dots" per inch, so the higher the DPI when printing, the greater the detail of the printed image. If you don't have a high enough DPI however, the printed image will be fuzzy/blurry because paper has a much higher resolution than most any monitor. What looks just fine on the screen can look like utter crap when printed due to this.

You can take DPI away when changing an image, but you can't add it back. To get higher DPI you need the original source image, and sometimes that source wasn't created with a high enough DPI for print to look good.

http://ne-ko-ma-ta.blog.ocn.ne.jp/blog/images/2010/05/10/kaizou04.gif

An image has three related properties:

- number of dots (1600x1200)
- number of inches, aka print size (20x15")
- number of dots per inch (80)

When you're talking about the resolution of a file on disk, the word "resolution" usually means the number of pixels in the image, but it can also refer to the DPI.

When you resize an image in Photoshop, you modify one of these properties, and the others change as a result. For example, if you change the above image to 800x600, then one of two things must also happen: either the print size changes to 10x7.5", or the DPI changes to 160.

In other words, you can increase the DPI, but when you do that you're also reducing the print size.

You can, in principle, take a 150 DPI poster and print it on an index card. The resulting DPI would be very high, since you're taking the resolution of the larger image and squeezing it into a small space. Similarly, you can take a telecard and make a poster out of it; the result is a very low DPI.

You can see how all of this interacts by playing with the Image Size dialog in Photoshop. You can change the pixel size, DPI and print size, but they're all naturally tied together.

There's little technical difference between "low print resolution" and "scanning_resolution" (though the artifacts may look different--printed low-res CGs tend to look aliased rather than blurry). The practical difference is that low print resolution is the book's fault, and is probably visible as a low-quality image on paper; excessive scanning resolution is scanning problem.