Photo Resolution

[phiblue29]

I have a question for you all--

What resolution do you set your images up as for photo labs? I know many that do not go all the way to 300dpi.

Just looking for opinions on what is being used.

In the print world most mags are 133 lpi, which translates into 266 dpi-- most people don't realize 300 dpi is overkill (only a few magazines-- Communication Arts and National Geographic are two) actually print @ 150 lpi.

Anyway-- I'm just looking for insight... what do you all think?

[jeffkohn]

You want to scale to the native resolution of the RIP or print driver used for printing, or at least to an even multiple. If you don't, the file will get interpolated to the native resolution anyway, which could cause interpolation artifacts and/or reduce the effectiveness of any final print sharpening that you applied to your image.

So for instance if printing on a Fuji minilab that has a native resolution of 300ppi, that's what you'd want to send to the print. If printing on a Canon inkjet with a native resolution of 600ppi you want to give it either 600ppi or 300ppi (going from 300 to 600 is a very simple interpolation step, you should be OK as far as artifacts go).

Note the number of interest here is the native resolution of the print driver, which is actually PPI; the hardware DPI number is not what you want to target.

[krodgers]

a few of labs localy are telling me to just send image as is, their response is our photoshop is more expensive than yours and our interpolation will do a better job. do they really have a more expensive version, that does a better job?

[MarekWK]

Originally Posted by krodgers

a few of labs localy are telling me to just send image as is, their response is our photoshop is more expensive than yours and our interpolation will do a better job. do they really have a more expensive version, that does a better job?

that's quite a claim - not sure if there is any substance behind it... if they are a good lab, you could find their printer profile(s) at http://www.drycreekphoto.com/ and turn over the images properly profiled. of course, that means your monitor is calibrated as well.

[epronske]

If I have to up size the image, then I usually upsize to 300 dpi and then sharpen the image on the upsized interpolated image. If I don't have to upsize, say for 4x6 prints by the lab, then I just leave the image as is and send it to the processor. I feel that I have more control and better know what the image will look like if I do the upsize interpolation and sharpen myself.

[CobyPhoto]

I definetly do not claim to be an expert on this, but I have comsulted with my lab several times about this issue. They don't have a more powerful Photoshop, but proferssional labs do have very effective and very expensive RIPs that out do photo shop's interpolation hands down.

Anytime I print large prints, I allow my lab to do the final interpolation with that more powerful RIP. My lab tells me to crop by setting the size, with NOTHING in the resolution box...keeping the resolution just as it came out of the camera.

I have printed many 30x40 prints in this manner with excellent results.

CJ

[jeffkohn]

I definetly do not claim to be an expert on this, but I have comsulted with my lab several times about this issue. They don't have a more powerful Photoshop, but proferssional labs do have very effective and very expensive RIPs that out do photo shop's interpolation hands down.

Some labs may be printing with high-end RIPs for Epson or other large-format inkjets. But I think that the prints most people get from the lab are done on Fuji and Chomira minilabs, and do not undergo high-quality interpolation. So IMHO anybody sending prints off to MPix, Costco, Walgreens, or any other corner lab should be interpolating (and sharpening) themselves if they want the highest quality results.

The problem I have with letting the RIP interpolate is that it means the process of interpolation and final print sharpening (if the latter is being done at all) are getting done by software. Call me a control freak, but I want to interpolate myself and exaimine the results to make sure there aren't any objectionable artifacts. I also want to do the final sharpening myself, because no automated sharpening tool can do as well as a person; when I sharpen I can make decisions based on the actual image content, and I can also use masks, L-channel sharpening, and other tricks that no RIP software can match without human intervention (and if you think lab techs are applying image-specific sharpening to your prints you're either kidding yourself or paying serious top-dollar for full-service "exhibition" printing).