Should a photo lab need to enlarge an image?

Just some background. Sent some photos off to get them printed. Cropped them in LR to 5x7, spoke with the lab about dimensions. They said for the 5x7 to use 3000 pixels on the long side. No problem set that up in the LR export filter.

Used the lab's software to preview photos, even ordered some samples and all looked good.

Send off a larger batch, get them back and they are basically enlarged/zoomed in on a good majority of the photos. Basically they are cropped even further cutting off some key elements of the photo. Lab said that it's standard practice that photos can be zoomed up to an additional 3%.

I don't print enough to know if that's correct or not, but it would seem to me that if the photo was sent at the correct aspect ration it shouldn't change.

The problem occurs because when you print borderless you need to ensure that there are no white strips left at the edges. To do this the rasterising process makes the image a few mm larger all round. The lab that I use reccomends leaving about 5mm (0.2") on each edge from any wanted detail. I usually place a 5mm border and usually end up with 2-3 mm left at the end. Even your home inkjet will do this when printing borderless. The bits cut off may not even be totally even as the paper may not be 100% square. Had this catch me out in the past when I first stared making prints.

Alan

Thank you. Makes sense.

Ok, so related follow-up question;

I had to print a few 3.5x5 photo at home tonight. I ran out of 5x7 inch paper so printed one on a 4x6.

I set this up in LR using the correct cell size. I placed the photo in the center of the page. When it printed the photo was ~1/8" larger than 3.5x5.

Is this due to the same reason?

Thanks

if you chose to print borderless, yep

I'd say yes, it's pretty normal. Plan for a bit of "fudge", then cut to the needed size!

Thanks. That's what I thought.

Have to say it would be nice if the crop marks that get applied in the LR print module (if you select that option) were actually the correct dimensions. Would help a lot when cutting.

For your local printer you can set up a custom preset that solves this problem with just a little effort. For example, make an image file using Photoshop or Elements that is nothing more than a thin stroke exactly 4x6 (or 5x7 or whatever you want to "calibrate" for). You can also add some other "boxes" that are, say. 0.1", 0.2", etc. smaller and/or larger to help see what is going on with the print. Print the file (it won't use much ink) and carefully measure how much it falls inside/outside the nominal size. Add these adjustments to the image size in the Print Module and save as a preset. Repeat and make any necessary tweaks and resave the preset. You may find that each edge requires a slightly different amount, such as 0.08" on one side, 0.12" on another, etc.

If you are printing an image size on your local printer that is smaller than the paper size, DO NOT use borderless as an option in the printer driver. If there is going to be white space anyway you do not need the printer to print right to the edge, so you do not need the printer driver to allow for any slight misalignment of the paper. This will then have the image printed at the "correct" size.

Alan