Hello everyone, I have a question, I am not sure this is the right place to ask, if not I am sorry.
Recently I asked a question on TeX.stackexchange here. I thought using TeX, I could not print images correctly. I tried printing the same images in MS Word, the result did not change.
The problem is on the printing process somewhere I suppose. On the way I learned about dithering, halftones and even a special chip called raster image processor. But unfortunately none of them helped me solve my problem, instead confused me further.
What I see in pdf and on paper does not quite match. My image's resolution is 300dpi, and dimensions are 256x256 pixels. So the actual size is ~2.17cm. Here is the comparison of the actual and printed images, note that because I am comparing some image processing algorithms original images are kind of altered.
How can I print small images so they look beautiful? In other words, I want the printed images to preserve their distinct features, like their squared patterns.
The problem is that most printers print black and white, and have to simulate gray tones in a variety of ways that trick the eye into thinking it sees smooth gray values.
It's not clear what kind of device you're using (laserprinter of some sort?) and whether you have to use it in the way you are. Some ideas that might give you the result you want:
- You could try increase the AM screen frequency (100 -> 150 lines per inch, for example) in the print driver
- If your printer supports any sort of dithering or FM screening, you could turn that on.
- If you're able to use an inkjet printer, you might get better results, since inkjets tend to use dithering automatically.
It looks like a fascinating exercise. Can you share what you're trying to accomplish/prove with this?
I have used a couple of laser printers but the results did not change.
The results I have shown here are from a laser printer at a photocopy shop. When I get back home, I will experiment with different settings and post the results here. I remember seeing halftone as a printing option. And there was an option to select the dither size 8x8 or 6x6.
I started to think only way to print these images is to scale them up (resizing), images will be blurry but the details are not visible anyway.
Ah Lena, she really deserves a rest after all these years!
Originally Posted by nimcap
I have used a couple of laser printers but the results did not change.
Laser printer results of using a traditional halftone screen can depend on the printer and driver and the software used to print to the printer. I would hope that the laser printer is at least 1200ppi resolution.
I started to think only way to print these images is to scale them up (resizing), images will be blurry but the details are not visible anyway.
Another option is to dupe the files and convert them to bitmap mode in Photoshop, selecting the "diffusion dither" option (I would experiment with changing the resolution at final print size to say 600ppi, 900ppi and 1200ppi). You will likely need to use a transfer curve to slightly darken the highlights and drastically lighten the image midtones and shadows in grayscale mode before converting to diffusion dither bitmap.
There are a couple of third party diffusion screen options which may also be worth looking at instead of Photoshop's built in dither:
Ah
Another option is to dupe the files and convert them to bitmap mode in Photoshop, selecting the "diffusion dither" option.
I used MATLAB to dither the image. Details are immediately lost in dithered images too. So I conclude that, images are too small to be printed correctly.
Original:
Dithered (little squares that is making the image are lost):
256 pixel original, resized down from a 512 pixel original that was better quality than the images shown in the original post.
Printed on a HP5000, at 1200ppi resolution, from Adobe InDesign with a 141 lpi halftone - print size being 2.17cm.
As the scanner is crap, the scan is not ideal. The image looks OK for what it is, when viewing the original print at 2.17cm in size. It is too dark, which could be fixed by lightening the image before printing.
@Stephen: My original images are supposed to look crappy As I said before I am trying some algorithms on Lena. You can see a square pattern on images. On the print you cannot see that square pattern. What I want is that square pattern is visible and comparable to other squared images. If I was to print original Lena, I would have no problems.
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Originally Posted by nimcap
As I said before I am trying some algorithms on Lena. You can see a square pattern on images. On the print you cannot see that square pattern. What I want is that square pattern is visible and comparable to other squared images. If I was to print original Lena, I would have no problems.
