Exporting to print at various sizes

Question

Hello,
I am new to Lightroom and would really appreciate some help! I give my clients their pictures on a cd/DVD to take to their prefferd printer and make prints in whatever size they like. However, I have been readings some forums and am confused about how to export my pictures so that they can be printed at any size but without having heads or feet cut off during enlargements,etc. basically, how should I export my pictures do that they can be printed at any size ( 4x6 or 8x10 pr even larger)without any loss of image. I currently have it set at 300 dpi and no sharpening because I do my sharpening in Lightroom. Please help! Newbie here!

Answer 1

>A print shop does not have to crop an image when they do an enlargement. And I don't think any print shop would do a crop.
Actually they do it all the time if the aspect ratio of the file you supply is not that of the print. They have to crop part of the image of if your image is 2x3 aspect ratio (i.e. a typical uncropped DSLR picture) and you're printing on 4x5 ratio (i.e 8x10, 16x20, etc.) or leave white strips on the side.
>I have been reading through this post and I am still very confused. I have an image in LR that I would like to print. The lab has asked me the usual (jpeg, SRGB, 300dpi) but also that it is no larger than 1MB per inch. If the raw image is 4928 x 3061, does this mean that I can only take it as large as 16.42 x 10.20 without loosing quality (4928/300dpi x 3061/300dpi)????
You should't worry too much about that 300 ppi figure. If your file is well captured (good lens, good technique) and appropriately input sharpened (the detail panel), you can get away with much lower numbers than 300. Certainly anything above 240 ppi will still look superb. Many people will go much larger than 12x18 from such a file depending on the subject matter. You can get away with that because people stand further away to look at larger prints. I wouldn't hesitate to try 20x30 with such an image for example. I would worry more about the fact that 4928/3061=1.6 while 18/12=1.5, so you have different aspect ratios (its longer than the printing size) for your file vs the print meaning that the shop will crop off the long ends. If you want to make sure the wrong things don't get cropped of by the printer, you should first crop to a 3:2 aspect ratio so can control the final print better. Also realize that print shops will employ a bleed where they will print the image slightly larger than the paper, so you'll always lose a part of the image on the edges so make sure you don't have stuff all the way touching the edges that you care about.
>I would love to print this image at 18 x 12 but whenever I upload it into the labs software, I am told that the file size is only 6.7MB - will this mean it will be poor quality???
No, jpeg filesize is not easily linked to quality. If you have large swaths of constant color and little noise in the image, you can end up with very small jpegs that have very good quality. Jpeg is a very efficient compression scheme and it is very good at throwing away information that is completely invisible to human eyes/brains.  You need to make sure that your jpeg quality is somewhere north of 90. Quality 100 is overkill. You cannot see the difference in prints even if you might potentially be able to see it on the screen. There is a good analysis here: Jeffrey Friedl's Blog » An Analysis of Lightroom JPEG Export Quality Settings
>Can I print this crystal clear at 18 x 12 and if so are my settings below correct?
These are fine. As I said, quality 100 is overkill for printing, my standard is 85-90 which is already a little much as there are very few pictures that need it but is a good compromise to me. You also should crop this file to 3:2 aspect ratio first before you do the export as the export panel resize will NOT crop the image for you, it will simply fit the image within a 12x18 rectangle.