For some time I wanted to have a few of my fractals printed and today I talked to a person in the printshop ,who said I could send them as JPegs and of high resolution .My usual resolution is 72 pixels per inch and when I raised it till around 300 P /pi the picture became enormous in size . Can anyone please tell me how it`s done . I use FE and Photoshop . Thank you , Dina

I use 300dpi too (exactly 12pixel/mm), and send image using a program which send the print to an online printshop. However you don't have to care about 'dpi' but only of pixels. 75x50cm=9000x6000 pixels. If i order a lot of prints i use jpeg compression, never go under 90% quality. at 89% the file is very smaller than 90% (i don't know why....), but there are some compression artifact. At 90% is ok. For compressing in jpg i use imagemagick (open source) instead of photoshop. I use it also to do high quality downsize to post here and in my website.

What size are you hoping to make the final prints? I know there is a formula, but it is based on the size of the final print x the dpi you want. If you want a 9" x 12" print, and you want it 100 dpi, you have to make it 900 pixels x 1200 pixels. Most printers want .tif files, so I am a bit surprised by the .jpg request. Also, you need to ask them if your files should be in RGB color format or CMYK color format. I hope someone with a bit more knowledge will jump in and help out.

Attached Link: http://www.fotofinish.com/resources/centers/photo/resolution.htm

I, too, am surprised that the printer asked for jpeg format as that is a compressed image format and some quality is lost by converting to that format, even at "minimum' compression. My printer accepts .psd's, .bmp's and .tiff's. I usually give him a .bmp file that he sometimes tweaks the sharpness and colors on with Photoshop b4 he prints it. For very large prints, 150dpi is ok but I wouldn't go any lower. I always render my stuff at 200dpi. The image size is just the number of pixels of the width or height of your image times the dpi you want. So a 20" x 30" print at 200dpi would be 4000 x 6000 pixels. If FE doesn't do anti-aliasing, you would have to render the image to a much larger size and then reduce the size to 4000x6000 with PS. Typically 2x works well so you'd need to do it at 8000x12000 to get a nice, smooth but crisp anti-aliasing effect.

Just have FE render your image to that size, if it can. I never used FE but I know XD doesn't let you make big images. You really can't just use Photoshop or PSP to enlarge a small image as the result is VERY blurry and not suitable for printing - or even viewing lol. There is a program called "Genuine Fractals" that SAYS it can enlarge stuff but it is expensive and I've heard not very good.

Once you get your big file as a .bmp, you can sharpen it in Photoshop using the "High Pass" filter. Duplicate the image on top of itself and then apply High Pass filtering (FilterOtherHigh Pass) to the copy layer with a pixel width setting of 0.3 or 0.4. I use 0.3 99% of the time. Use a setting that gives the sharpest edges without showing any or much colors other than greys. Any higher than say 0.6 will blur things and might dork with the colors especially at the edges of shapes. Then, go to Image/Adjustments and select "Desaturate" to make sure the copied layer is totally greyscale and won't mess with the colors of your image. Then Change the Merge Mode of the copied layer to "Soft Light" or "Hard Light". I usually use hard light as it is crisper but it brightens the image more than soft light does. "Vivid Light" works, too. Then do a Layer/Flatten or press Cntl-E and save the sharpened image and you're ready to rock!

One thing you might find is that the print could be much lighter than what you made on your pc. I've done an "Adobe Gamma" calibration to my crt monitor but it is getting old, so it won't go bright enough but if yours is fairly new, it sould work. Or you could spend some $$ and by a Pantone Spyder monitor cal thingie that attaches with suction cups to your monitor and senses it's setup. Then you'd have an ICC file the printer could use to tell his machine how things should look. At least I think that's how the Pantone thing works - I might be full of it - lol. I don't have one - yet. Also, make sure your Color Preference is set to "Adobe 1998" rather than "monitor...something" (don't have PS here at work to check the exact wordings) as this color setting is something the print machines software understands.

Good luck - you will be astounded by how fractals look printed very large and "in your face"! Hope this stuff is right - it's just the way I've done it.

Rick

Message edited on: 03/16/2006 08:47

Message edited on: 03/16/2006 08:48

My online shops accept bmp too, but the server space limit is 350MB per user, so i prefer jpg. To reach a reasonable price i have to order a lot of prints (price go down with number of prints, and also spedition cost per print is lower). I use a 3x3 antialias internal to my program (that do an armonic means of number of iteration, discarding the min and the max value, not colors). Sometimes with very complex fractals like my last ones i posted here i need other 2x2 or 3x3 interpolation (i write another program that divide the source bmp resolution by meaning pixels), so it's a lot of cpu work to do very large prints at 300dpi. A suggestion: I order my low size prints (up to 75x50cm) in a photo shop which probably use chemical print, the detail is good, but te color is not so good. The price is very low. If you can afford an higher expense i suggest you to do a print on an 6-colors plotter (not 4 colors!) on high quality photo paper. 6 colors is very good to print bright colors.

Thank you all for your helpful advice ,I think it`s clear to me now how to go about it . Dina

I use the .bmp format because I physically go to my printer's shop and bring him the files on a CD. That way I can "supervise" the print and get exactly what I want.....which is usually what he suggests it should look like - lol. What can I say, the dude is a pro! lol Hey, Dario - what program do you use to anti-alias your images? That would be great to know for stuff that I've composed in Photoshop rather than UF. Rick

Of course i also use bmp if i go tothe shop in my city. Unfortunately that shop is very expensive, and i went there only for one of my prints, that was too big to print online. I use always the internal 3x3 antialias of my fractal program, which don't works on colors but on numerical values. If it is not enough i've written another simple application that means pixel (takes nxn square and create a mean pixel). This is because some of my images get bigger than 1GB and there are memory problems to open such images. It resize one row at a time so it needs less memory. It is written in c, and actually it is not usable without a compiler. I will work on it to produce a command line interface..... stay tuned :-). Don't expect too much, i'm only a programmer hobbist.

http://xoomer.virgilio.it/jbgenov/resizer.exe (copy & paste this link on your browser, or it will not work) Usage: resizer.exe n input.bmp output.bmp n is the downscaling factor. source must be width multiple of 4*n, and height multiple of n. Work only on .bmp