Continuous tone prints

[Dare1325]

I'm fairly new to this digital world and learning all sorts of stuff about digital photography and the 10D. I've been reading about dpi, resolutions, pixel size, and such. As I understand it if I'm taking my files to a photographic printer (say the Fuji Mini Lab at a Wal-Mart) and having 4"x6" prints made, then the dpi doesn't matter, because it is a "continuous tone" print. Is this correct? So how do I know I'm getting the best quality? What should I adjust the Image Size in Photoshop to? Or does that not matter? How do things like resolution, pixel size and dpi relate to "continuous tone" prints? Thanks for any help you can give.

[cowman345]

I've had great results with the aladdin printers at walmart with photos with image size 4x6 and resolution of 300dpi (max that the aladdin allows, i think.)

However, I'm very interested in hearing from someone who knows more about this...??

-dave-

[evilenglishman]

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[cowman345]

So for highest quality large prints (8x10, 11x14, etc) do you have a lab you'd reccomend?

I've been using Adorama with nice results, but I'm interested in bringing my work to the highest quality level possible.

-dave-

[Webster]

Dpi does matter, whether or not you're outputting to a continuous tone printer. The details of the image are contained in the pixels, and the more pixels there are the more details. The misunderstanding might come with the difference between a dot on a continuous tone printer and a dot on an inkjet printer. On the former, a dot is the same as a pixel. On the latter, a dot is either a drop of ink, or whatever the printer's marketdroids decide it is. On a seven color inkjet printer, it can take seven dots to make up a pixel. But because printers play all kinds of dot placement tricks to improve quality, there is no formula I'm aware of to derive an inkjet printer's effective pixels per inch from its rated dpi.

[pwagner]

The inject printers that are popular for home users squirt ink onto the page. They can't vary the amount or intensity of the squirt so it is all-or-nothing. So, for example, to get a 50% grey tone, they alternate between squirting and not squirting adjacent pixels on the page--with a magnifying glass, the page will look like a checkerboard of areas of black ink with white paper showing through. This means that you want an inject printer with a truly massive "dpi" rating so that the dots aren't noticeable. Even a 1000 dpi printer will show lots of speckling in blue skies, for example.

The Fujitsu and Noritsu printers found at 1-hour-photo places (I use Costco and love it) use a photographic printing technique that allows each pixel to be varied in intensity. Even though these printers are "only" 300dpi (360dpi for the Noritsu), the results are nothing short of fantastic because of the smooth variations in color availble with the printing technique that the use. No speckels.

Don't get hung up about the 300dpi print resolution verses 1000+ dpi resolution of injects. The 300 dpi photomarts will give you MUCH better pictures.

If shooting with your 10D in JPEG with default color space (sRGB colorspace), then here's an "easy" workflow that will get you started:
(1) Open picture in Photoshop Elements and select the option to use the picture's sRGB colorspace; do NOT convert to Adobe RGB
(2) Adjust Brightness & Contrast to +15 and +15
(3) Adjust the Saturation to +25 (yes, that's going to look a bit high, but I feel that the Noritsu printer tends to tone things down when printing) I'm guessing that the Fujitsu will need a little less... +15 perhaps.
(4) Unsharp Mask to taste (not needed for 4x6 sized prints, but +135, 1, 1 for larger sized prints would be a good starting point)
(5) Do a "Save As" (DON'T OVERWRITE YOUR ORIGINALS!!!)
(6) In the Save As dialog select Quality 10 JPEG and make sure the checkbox for storing the color profile is marked. Type in a NEW NAME so you don't clobber your originals. (Actually, I write-protect my originals when I download them to my hard drive.)

I find that burning all the pictures to CD is fast and convenient. You can instead put the picture back on your Camera's CF card and take that with you. (The CD is MUCH faster and you won't care if it gets lots/broken/damaged, etc.)

[DAMphyne]

Olympus makes a pretty good at home dye sub printer, the P400. I've seen it on E-bay for about $250-$300 US.
Print cost, $2 per 8x10.
It requires that you send the file to the printer at 314 dpi. I've used it for doing "print on the spot" jobs and it does a pretty fair job, once you get it set-up.
Most ink jet printers want a file of at least 240dpi, but sending anything over 300dpi just causes the printer to take more time(and probably waste ink).
When you go to the photo processor, ask them what resolution you need for printing, then pre-set your images to the needs of the type of printer they use.
If the operator can't find out what is needed, look for another processor.
I agree with pwagner, always use "save-as", to protect your originals. It's one of the best rules to follow.