Pixel Quality for Files Going to a Photolab

[Kwallamonger]

This is my first post. I searched the site but couldn't find an answer so forgive me if this has been addressed.

I'm getting ready to work on a bunch of files from my D70 thatI took for a local theatre. The parents of the kids in the production are going to want prints. What is the best possible resolution to use when I just plain resize or set the resolution level in when I crop? I will save the final files in a Tiff format and I want them to be real high quality for the parents.

[Jodi Frye]

by going to image>resize>image size and 'unchecking' resample (important) and then putting in a dimension for width or height ( the other will automatically resize itself) will give you the best possible 'highest' res for print. You probably already know this but digital image aspect ration is different than film so you wont get an exact 5 X 7 , 4 X 6, 8 X 10 etc...so you will need to crop afterwards. The crop tool has presets for these common image ratios. Are you printing yourself or sending out ?

[Jodi Frye]

doh ! I just read the title thread...' going to photolab'...ok then...you should be all set with that.

[Kwallamonger]

Thanks. I noticed that when I use the crop tool there is a resolution box there. Should I keep this blank or should I enter the same resolution that it adjusted to when I resized?

[Jodi Frye]

Go ahead and leave that blank...otherwise it will downsample the image...no need to do that ;) I honestly have no experience with photolabs tho...not sure how they handle high res images...If it were me I'd give them the highest possible ppi to work with....hopefully they'll know what to do with it.

[Linda559]

I use the D70 myself and the cool thing about it is the images are already proportioned for 4 x 6. This is called Full Frame. The other full frame sizes are 8 x 12; 10 x 15; 11 x 17 and 16 x 24. I believe these are correct.

If you need 8 x 10 and 11 x 14 try to remember to shoot a little bit wider or you may loose some of your subject when you size the image.

Now for my method. I simply choose the crop tool and enter my dimensions into the crop boxes at the top of the screen.

I'll enter 6 x 4 and leave the resolution blank. Then just drag the crop tool across the image to 'frame' your 6 x 4 image. You can drag across the entire image, or drag across just the area you want to use for your 6 x 4 print. I frequently will crop a smaller area to tighten my shot a little making my subject more predominant in the print.

Remember, you have a lot of resolution to work with. I can crop a fairly small area as my 6 x 4 print and still have sufficient resolution for printing.

ALWAYS use your D70 at the highest resolution and 'fine' setting. No use in having a 6.2 Megapixel camera and use it as a 3 MP camera.

It's late and I'm wired on caffeine, so if you have any other questions or I've confused the issue - let me comment more after a partial night's sleep. :shock:

Linda
http://www.pbase.com/linda559

[Kwallamonger]

Linda-
I've been away and just got back to your post. Hopefully you are still connected.

Can you explain the "Full Frame" thing. I went to the manual and couldn't find anything about it. When I open a picture I just transferred from the camera and I look at the "size" PSE tells me it is 6" X 10", not 6X4 or 4X6. I do shoot in highest res and finest quality (though not RAW). I'm interested in hearing more.

[pardo]

how big of a print can you make with a 4 meg camera without losing quality.

[Carbone]

Kwallamonger :

Full frame means that what you see is what gets printed, in other words, the aspect ratio of the picture matches the one of the paper. 4 x 6 is 1.5 (4 times 1.5 = 6, or if you like it the other way, 6 divided by 4 equals 1.5). To determine if a camera makes full frame (or not), divide its longest side by its narrower. If the result is 1.5, you've got a Full Frame camera.

On my Canon 10D, the maximum size of a picture is 3072 x 2048. And, 3072 divided by 2048 = 1.5, or full frame. This would print perfectly on a 4 x 6 paper.

Smaller camera (i.e. like the Canon Powershot A510) will make 1.33 aspect ratio pictures. In order to fill a 4 x 6, one side is cropped.


pardo :

The optimum resolution is 300 pixels per inch. Divide the dimensions of your camera's picture by 300, you'll have the best size possible. For example, my Canon 10D produces pictures of 3072 x 2048. At 300 pixels per inch, this gives 10.24 inches x 6.82 inches. That's the optimum resolution. For 4 x 6 and 5 x 7, it's best to keep the resolution to 300 or close to. Because those pictures are seen from close, usually (in hands or in albums held at arm distance), the least details lost will be noticed by the viewers.

If you want to print larger pictures, 8 x 10, 11 x 14 or 13 x 19, 225 to even 180 pixels per inch will give ok results. Because those pictures are usually kept at a distance from the viewers (hung on a wall, at a certain distance from the ground), the loss of details is less visible. I have pictures made at 180 pixels per inch hung in my living room, no one can tell because they're far enough.

Ray

[Karren]

Ray

Thank you for that explanation. I finally understand the resolution size per print size. It has been bugging me for the last year or so. You have put it into words that finally got thru my thick head. Thanks!

[Anonymous]

Ray,

At the highest quality settings on my D70 I start with an 10.027 x 6.667 at 300 pixels per inch. Is there a way to maintain that 300 as a minimum while increasing the size and not resampling the image?

Do you think 300 pixels is a good quality resolution for processing a photo thru a lab? Do you know if a higher resokution will create a problem for a lab?

Thanks for your help. It has been quite valuable.

[Carbone]

No, you can't get more than 300 per inch if you wish to keep 10 inches. 300 pixels per inch is actually the exact number of pixels your image has, divided by 10.027 inch. You cannot get more pixels per inch at this dimension because the exact number of pixels in your image isn't going to change.

10 apples, for 5 kids, makes 2 apples per kid.
10 apples, for 10 kids, makes 1 apple per kid.
At the end, you still have 10 apples. Only, you distributed them differently.

It's the same thing for pixels per inch. An image of 3072 pixels wide (or tall) will make 300 pixels per inch for 10 inches long (more or less). If you want to have more pixels per inch, either the width of your document will decrease (600 instead of 300 will reduce by half the size) or will have to create new pixels. Upsampling is never a good idea, unless you're forced to.

As for a Lab, I can't tell. But, if you do business with a pro camera store, I suggest you call them first and ask them about this info. Share the answer with us, of course :)

300 pixels per inch (up to 360, generally) is for Inkjet printers. For laser or other means of processing, it might be a different setting.

Hope this helps !

Ray

[smorky]

If you look for detailed information on resolution for scanners, printers, and monitors, try this pages. http://www.scantips.com/ It might also be helpful for digi cams.

I didn't browse through yet, but it seems to contain a lot of information and starts from the basics. Maybe that helps.