I've not tried to do precisely what you want to do in LR2 Mogrify but I send jpeg files on a fixed canvas size for the aspect ratio for varying image ratios in the way described below.
First make the canvas 1800x1200 pixels (in white if your borders are white). This is, of course, 6"x4" at 300dpi and 3:2 aspect ratio.
If you are starting with an image (including the various border widths) at 3:2 aspect ratio resize the image to be 1800x1200 and the canvas size plays no part, unless you want to add a little extra for trim variations for example 1782x1267 to gives a few extar pixels leeway.
With images at a different aspect ratio from 3:2 resize so that the longest dimension corresponds to the maximum number of pixels you need. The sizing and canvas sections in LR2 Mogrify need to be active for you to access them
Message was edited by: effeegee typo corrections and clarification
This seems to have worked, I did what you suggested above in your 3rd sentence (without the canvas). I set the aspect ratio 3:2 on the image in "Develop" in LR, I uploaded the images to the photo lab and I did use the crop tool in their program, because if I left it uncropped, the side borders were fat, but it gave me my full image after I applied the crop to the picture, wierd. I pick up my test picture tomorrow. If all goes well, I have 400 pictures to apply this pre-set to before Christmas. Here are screen shots of what I did in LR4 Export:
I will let you know how the picture turns out, here's hoping!
Thank you so much for answering my question.
This sounds like an excellent feature.
Does anybody know, if you really need to type custom text identical for the export batch in this Mogrify section of the export dialog?
Or would metadata fields such as Title or Caption be available?
Another question: have you tried this, without plugin, from the print module - where those metadata are available? What is the result / what are the shortcomings vs. Mogrify?
I got my pictures back. This did not work. My border was cut-off as was the second line of text. I am thinking I have to make my "resizing" smaller to accomodate the borders. Or try the canvas again. The canvas just isn't working and I know it has to do with the numbers but I don't know what to put. So frustrating.
Maybe it would be worth while to inquire at your lab supplier what their specifications are.
Because if they should per default regard any white border space as free to cut off, it would not work, no matter which exact dimensions you try.
Obviously their preview does not seem exact, otherwise you would not have cropped in their tool...
I looked at your screen shots in more detail.
The resizing options are different with the resize tab in LR2 Mogrify from those in the native Lightroom options which you have used. They may conflict if you use both. I prefer to use LR2 Mogrify since this is what drives your borders as well as whether outer borders are included in the image and if the aspect ratio is maintained.
The canvas size determines the overall file dimensions in pixels (with padding when required). The file dimensions in pixels will get converted to inches or millimetres by the lab's printing resolution. So even if the resize is to 1800x1200 pixels in the LR2 Mogrify resize tab I would make the canvas size 1800x1200. It just implies that the canvas and image are the same size and that no padding would result. If you enter 99% of 1800 x1200 (1782x1188) you should get padding of 9 pixels and 6 pixels in the sides, top and bottom margins respectively.
By the way I would not limit the file size to 350Kb the final size of the file will relate to the pixel dimensions.
A quick test of what your settings achieve would be to have the canvas set to black. Then satisfy yourself that a little but consistent padding strip results when your print or view the exported JPEG file. If you are still struggling why not try and post this with the appropriate screen shots and it might make clear what is going on.
I hope you are not having to enter the description on each photo. That looks very tedious.
I have pretty much put my image and canvas to 1782 and 1188 respectively. Yes, I need to put a description for each photo. These photos are from the 50's and I want this information on the front of the photo. I am doing a DVD with a set of the regular images and a set of the caption images for most members. I am doing the captions to print for my father in-law who took these photos and is now 83. We are putting these images in an album. These were all slides before. I compressed the size, because the pics were over a 1MB each. The quality of the picture is very good from the photo lab. borders are still a little wonky, but at least the photo lab no longer wants to crop the image. I should not have cropped the image before, because that is what gave me my poor results. If I keep having problems, I will post the screen shots and a sample picture, if this site will let me post a pic. Thank you for your help