resolution, DPI and printing or showing your photos

[Marquinius]

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I had the feeling that something lacked in my understanding of DPI and printing. I found this interesting link with a clear and concise explanation with a couple of examples. Worth reading if you want to get better prints and want to understand what's what when putting on the web.

 

In short as I understand this story: my M8 has a native (on paper) print resolution of 13 inch x 8.7 inch at 300 DPI. Which means that when I want to print bigger, I either have to resize the photo or lower the DPI. When I print smaller, the extra information will just be ignored.

[Shootist]

Not really sure abnout the last part. My printer has a resolution of 1200 dpi so I take it that I can print M8 files at that PPI resolution and get a image on paper 3 1/4+" x 2 1/8+".

 

I have printed images with a PPI resoution as low as 140 with good results. But normally I will use either 300 or 240.

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[delander †]

For printing I resize to 240 ppi and then upsize if required in PS.

 

Epson I think would like 360 ppi files but I get great results using just 240. On occasion I have gone down to 180. With care I can readily print an M8 file at A2.

 

Jeff

[luigi bertolotti]

I had the feeling that something lacked in my understanding of DPI and printing. I found this interesting link with a clear and concise explanation with a couple of examples. Worth reading if you want to get better prints and want to understand what's what when putting on the web.

 

In short as I understand this story: my M8 has a native (on paper) print resolution of 13 inch x 8.7 inch at 300 DPI. Which means that when I want to print bigger, I either have to resize the photo or lower the DPI. When I print smaller, the extra information will just be ignored.

 

Sorry... I cannot see the link: I am interested so I like to read it... can youre-post please?

[buckhorn_cortez]

In short as I understand this story: my M8 has a native (on paper) print resolution of 13 inch x 8.7 inch at 300 DPI. Which means that when I want to print bigger, I either have to resize the photo or lower the DPI. When I print smaller, the extra information will just be ignored.

 

You have to understand the native resolution of your printer. Most Epsons are 720 dpi, Canon and HP are 600 dpi. This is interpolated by the printer driver to a stochastic dither pattern that is much higher final dpi - like the epson 2880x1440 highest quality.

 

However, you have to understand that even at the native image size (300 ppi generating a 13 x 8.7 inch print) the printer driver is doing interpolation to get the image first to the native resolution (720 dpi or 600 dpi) so that it is formatted correctly for the stochastic dither at the selected printer resolution.

 

When you go larger than the native image size, there are a number of different approaches.

 

1. Resize the image and send a lower ppi image to the printer and let the printer driver interpolate to the final size. Not the best way - printer drivers aren't very good at interpolation and you will find jagged edges, and reduced textures.

 

2. Resize the image using PS (or other image processing programs) with something like bicubic smoother. Does an okay job on moderate size increases. On large images (like an M8 at 18x29) the image loses both color saturation and sharpness.

 

3. Use a dedicated software interpolation program - many available, most have some type of problem like artifact generation, resampling errors, etc.

 

4. Use raster image processing (RIP) software to interpolate the image. The best, and most expensive method. The RIP drives the printer directly and bypasses the printer driver. The RIP provides much better control over the printer including: better stochastic patterns, better interpolation, sharpening on output, and total control of inking by color. RIPs format the image at the resolution selected for the printer. Some RIPs will change stochastic patterns to provide the best image at the selected resolution.

 

5. Lastly, there is Qimage that is a dedicated printing software. It formats the image at the printer's native resolution (720 or 600), has much better interpolation than the printer driver, image processing programs, or dedicated software interpolation programs. It also provides sharpening on output.

[Marquinius]

Sorry... I cannot see the link: I am interested so I like to read it... can youre-post please?

 

Ahh ...Luigi, I got called away (by a drink with my wife )

 

http://x-equals.com/blog/?p=2653

 

And yes, with a lower resolution one can print bigger, but one loses detail.

 

And no, I don't think the 1200 DPI of the printer is the issue, the native resolution of your camera at a certain DPI is. If you want to print at 300 DPI with a file out of an M8:

- 3904 pixels : 300 = 13 inch

- 2622 pixels : 300 = 8.7 inch

 

My idea is, that if I let Lightroom go ahead and print at A3+ without resizing the photo, it will mean loss of detail. Lightroom resizes it drastically in one go. I've read that resizing (upsizing) should be done at 110% steps to keep the best detail.

[Marquinius]

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You have to understand the native resolution of your printer. Most Epsons are 720 dpi, Canon and HP are 600 dpi. This is interpolated by the printer driver to a stochastic dither pattern that is much higher final dpi - like the epson 2880x1440 highest quality.

 

However, you have to understand that even at the native image size (300 ppi generating a 13 x 8.7 inch print) the printer driver is doing interpolation to get the image first to the native resolution (720 dpi or 600 dpi) so that it is formatted correctly for the stochastic dither at the selected printer resolution.

 

When you go larger than the native image size, there are a number of different approaches.

 

1. Resize the image and send a lower ppi image to the printer and let the printer driver interpolate to the final size. Not the best way - printer drivers aren't very good at interpolation and you will find jagged edges, and reduced textures.

 

2. Resize the image using PS (or other image processing programs) with something like bicubic smoother. Does an okay job on moderate size increases. On large images (like an M8 at 18x29) the image loses both color saturation and sharpness.

 

3. Use a dedicated software interpolation program - many available, most have some type of problem like artifact generation, resampling errors, etc.

 

4. Use raster image processing (RIP) software to interpolate the image. The best, and most expensive method. The RIP drives the printer directly and bypasses the printer driver. The RIP provides much better control over the printer including: better stochastic patterns, better interpolation, sharpening on output, and total control of inking by color. RIPs format the image at the resolution selected for the printer. Some RIPs will change stochastic patterns to provide the best image at the selected resolution.

 

5. Lastly, there is Qimage that is a dedicated printing software. It formats the image at the printer's native resolution (720 or 600), has much better interpolation than the printer driver, image processing programs, or dedicated software interpolation programs. It also provides sharpening on output.

 

 

Exactly as I understand it.

[haroldp]

buckhorn_cortez is exactly right, Qimage is the best $ 59 I ever spent on this hobby. It automatically resizes and interpolates based on your final print size and it's interpolation is infinitely better than any print driver, and significantly better than PS.

 

I value this software so much, that I run a windows guest machine under parallels on my mac-pro to use it.

 

600 dpi is magic on an HP Z3100. 1200 seem to just take longer and use more ink.

 

Regards ... Harold

[erl]

An emphatic vote for the Qimage option. I don't know exactly why it works, but it does! I spent squillions on RIP's , RAP's & RUMP's or whatever and Qimage licks 'em all, not just for the actual printing, but for handling multiple prints and fitting all sizes to a given page size, and so on. Qimage + Epson 3800 combo saved my bacon just as I was about to give up digital printing. Now it is a breeze.

[Marquinius]

I value this software so much, that I run a windows guest machine under parallels on my mac-pro to use it.

 

 

I read about this set up, but need some refreshment of thought. You do your DPP in OSX, then switch to Windows through parallels and print? I'm not familiar with parallels: does that work in a screen within your OSX environment?

 

I can look it up, no worries. Qimage, hmm. OK, will have a look.

[Shootist]

buckhorn_cortez is exactly right, Qimage is the best $ 59 I ever spent on this hobby. It automatically resizes and interpolates based on your final print size and it's interpolation is infinitely better than any print driver, and significantly better than PS.

 

I value this software so much, that I run a windows guest machine under parallels on my mac-pro to use it.

 

600 dpi is magic on an HP Z3100. 1200 seem to just take longer and use more ink.

 

Regards ... Harold

 

After years of hearing about Qimage I finally said what the heck and bought it. Just a few minutes ago I took a shot that was taken yesterday morning and printed it through PS CS4 and the latest version of Qimage. At first glance I said OK it looks a little better but then I looked at the 2 prints with one of those sensor loupe magnifiers and boy what a difference. The test was done on 8.5x11 paper and both Qimage & PS were set to fit the image to the paper.

Next test will be on a normal size M8 image printed to 13x19 inch paper without using PS to resize it 12x18. I'm going to use a olde image that I have already used PS to print to that size paper.

[roguewave]

I have an old HP 7960 photosmart that I use to make small (5x7) prints to folks I take images of on the streets. I always send them a full size & smaller size file that they can use to make any size prints in the future. Does anyone know if Qimage is a better way for me to make these prints? I didin't see any thing regarding this HP printer on their website & I must say I'm in the dark ages when it comes to printing. I have used a lab for all my larger (larger than 8x10) prints. Does this apply to B&W as well as color? Thanks, ben

[erl]

Ben, I am a great enthusiast of Qimage, as you may have noticed. The trial version is free, the licensed version is cheap, if you favour it. I believe it will very easily do what you want, and more.

 

It very easily lays out multiple as well as single copies of any size image on a selected paper size, providing they will physically fit of course. You can also 'print to file' instead of your desktop printer and control the quality you wish to create. This would be ideal for the files you send to friends etc.

 

If you need more info or help, feel free to contact me by PM. I can offer my experience with the software as it is so far, and still learning.