about print 4x6 with a 10MP resolution

shingfan · Jan 30, 2007

i wonder.......my camera's resolution is 10MP (D80)....if i were to print 4x6....should i just use the 10M resolution files...or should i resize them to something smaller....like 2000x3000?.....because when i view the files on my computer....they look sharp....but as soon as i print them....they come out very flat.......and i had similar party pictures taken at 6MP with a different camera....they came out sharper than my D80..but when those pictures are viewed on the computer...the 6MP ones are very noise and not as nice compare to the ones taken by my D80.......???? i print the photos are walmart (not to mention that their prints are so brownish...all my pictures come out so dark and brown compare to when the pictures are viewed on the camera and computer >_<)

c_mac · Jan 30, 2007

before you print anything you should always check to make sure that the actual image size is what you want to print to.

my 30D shoots in a wider format than 4x6 so i have to actually crop off some of the image to get the correct proportions. so what is probably happening is the printer is making doing the rescaling for you, causing it to come out flat. this would also be why the 6mp doesn't look as bad printed, it doesn't get "rescaled" as much.

in photoshop go to image>image size check here to see what the actual dimensions are. but what i like to do is using the crop tool set the dimensions you want, in this case 4x6, then just start from one corner and go to the opposite corner...and hit enter.

Digital Matt · Jan 31, 2007

The 30D's sensor has a 2:3 ratio, which means you don't have to crop 4x6" prints. The same is true of the D80.

Walmart is printing at 300 DPI. You need to set your pixel resolution so that it will give you the size you want at 300 DPI.

A 4x6 is 1200x1800 at 300 DPI. 1200/300 =4, and 1800/300 = 6. Do this in photoshop via image size. If you are resizing something down, always give it an unsharp mask afterward.

Now the reason they are flat probably has to do with color space. Find out what color space they are using. My guess is that they have a Noritsu machine, and it wants sRGB. Most commercial photo printers use sRGB. You are probably using AdobeRGB in photoshop, and when they make the conversion, they are throwing away alot of color data, hence the flat look. You have to make the conversion on your end. Another factor is that your monitor is obviously not calibrated to their machine. Your color may never look the same. You'll have to do some experiementing to get your color accurate. My advice is to find a local pro lab to get your prints made, so you can talk to someone who is knowledeable about the color management.

ksmattfish · Jan 31, 2007

Calibrate your monitor, and find a better lab.

shingfan · Jan 31, 2007

Digital Matt said:
The 30D's sensor has a 2:3 ratio, which means you don't have to crop 4x6" prints. The same is true of the D80.

Walmart is printing at 300 DPI. You need to set your pixel resolution so that it will give you the size you want at 300 DPI.

A 4x6 is 1200x1800 at 300 DPI. 1200/300 =4, and 1800/300 = 6. Do this in photoshop via image size. If you are resizing something down, always give it an unsharp mask afterward.

Now the reason they are flat probably has to do with color space. Find out what color space they are using. My guess is that they have a Noritsu machine, and it wants sRGB. Most commercial photo printers use sRGB. You are probably using AdobeRGB in photoshop, and when they make the conversion, they are throwing away alot of color data, hence the flat look. You have to make the conversion on your end. Another factor is that your monitor is obviously not calibrated to their machine. Your color may never look the same. You'll have to do some experiementing to get your color accurate. My advice is to find a local pro lab to get your prints made, so you can talk to someone who is knowledeable about the color management.

i guess finding a pro lab would be a better approach....but before i do that....what would be a good tool to calibrate a samsung LCD so that when i print the photo at the lab i would expect a similar color output?

ksmattfish · Jan 31, 2007

I'm using the X-rite Monaco Optix XR calibration kit, and it's worked very well for me.

This site has lots of hands on reviews of calibration gear, and other good stuff. You have to register (free) to get access to most of the articles, but it's worth it.

http://www.shootsmarter.com/

shingfan · Jan 31, 2007

ksmattfish said:
I'm using the X-rite Monaco Optix XR calibration kit, and it's worked very well for me.

This site has lots of hands on reviews of calibration gear, and other good stuff. You have to register (free) to get access to most of the articles, but it's worth it.

http://www.shootsmarter.com/

when you calibrate your monitor....do you need any hardware for doing the job?...or you can calibrate with software only?

Digital Matt · Jan 31, 2007

You can calibrate it with Adobe gamma and no hardware. The hardware then becomes you eye, and this lets in lots of potential errors into the process. It's better to use a kit like Matt described, which utilizes hardware and software.

shingfan · Jan 31, 2007

yes....my eyes are no good in calibration....i think my monitor comes with some with sort of calibration tool as well........so how much are those kit and where can i buy them from?

Digital Matt · Jan 31, 2007

Try google.com

MACollum · Jan 31, 2007

Digital Matt said:
A 4x6 is 1200x1800 at 300 DPI.

When I convert my images from DPP I usually resize the JPGs to that size/resolution to save space since I upload my pics to an online printer.

BTW, I've had good experiences with printing at Walmart but the last few times I didn't get good results, although this is probably somewhat dependent on the people who actually run the printer.

shingfan · Jan 31, 2007

i used to have "ok" quality from walmart too...but ever since i have my D80....the quality come out worse than i expected..why i start to feel that their machine is not able to do a good resizing job on resolution that is 10MP or above...in terms of color....i think it depends on the operator i guess.....color always vary from time to time...haha....(this time is brownish....to me...they are not so good....but for average ppl....they are still nice....since they only have P&S and those are not comparable to my DSLR with external flash)

Digital Matt · Jan 31, 2007

MACollum said:
When I convert my images from DPP I usually resize the JPGs to that size/resolution to save space since I upload my pics to an online printer.

What if you want to make a print bigger than 4x6? You really want to go back and re-convert the raw file for every print?

why i start to feel that their machine is not able to do a good resizing job on resolution that is 10MP or above

Changing resolution has nothing to do with color, but sharpness it will. The problem lies with you. It's your responsibility to give them a good file. The tech at Walmart doesn't really care about your pictures, and certainly is not going to sharpen them for you. Resize it yourself to the dimensions you need and sharpen as necessary. Find out what profile they are using and color correct your images after converting to that profile. Then if the pictures still come out looking bad, you'll know it's just them.

shingfan · Jan 31, 2007

Digital Matt said:
Changing resolution has nothing to do with color, but sharpness it will. The problem lies with you. It's your responsibility to give them a good file. The tech at Walmart doesn't really care about your pictures, and certainly is not going to sharpen them for you. Resize it yourself to the dimensions you need and sharpen as necessary. Find out what profile they are using and color correct your images after converting to that profile. Then if the pictures still come out looking bad, you'll know it's just them.

yes...changing resolution is to resolve the sharpness issue...color is still on my end to make sure what they use as color profile.....i'll try to figure out next time i visit the walmart that i often go to.....if still bad...i'll just use a different store for more important printings.....

i also find that their prints usually have color cast or high saturation sometimes....or that is also a result of mismatch color space?

Digital Matt · Jan 31, 2007

shingfan said:
yes...changing resolution is to resolve the sharpness issue...color is still on my end to make sure what they use as color profile.....i'll try to figure out next time i visit the walmart that i often go to.....if still bad...i'll just use a different store for more important printings.....

i also find that their prints usually have color cast or high saturation sometimes....or that is also a result of mismatch color space?

Certainly could be a color space mismatch problem.