Dimension resizing not working | time sensitive!

Question

Using LR 4.0, MacBookPro
Hi All, I really need some help. I am trying to export a jpg to Dimensions OR Width x Height:  1224x2048.
I cropped the image in a 4x6 aspect ratio, portrait orientation.
The jpg is not exporting to these dimensions. It'll give me the width, but not the height. The height is topping out at 1836 pixels.
I've exported without size constraints, and it'll give me dimensions 1941 × 2912 pixels, so the pixels exist to be used.
**Do I need to crop to a different aspect ratio to get 1224x2048? **
What am I doing wrong here? I've got a freaked out client, I'm on a tight deadline, and I feel like this worked last week when I tried it, but maybe it did not.
I tried looking on the Adobe forums, no luck other than the usual instructions on cropping.
Help?!
Thank you so much!!

Answer 1

In cases where you want to export a JPG to specific pixel dimensions (and therefore, to an imposed aspect ratio) you may not want to upset your current crop, and the aspect ratio which belongs to that.
You can make a virtual copy, and re-crop that. Or you can make and then later recall  a snapshot, or use the History in order to return to your prior aspect; but this is maybe a little laborious.
There is a workaround via the Print module (using that to export a JPG) which does not involve changing your crop at all.
By starting from a print setup where a borderless printing mode is selected in the printer settings, you can fill the "page" displayed with your image, leaving no margins. Or you can have margins as a "frame" where the page background colour which shows here, is controllable - or you can use a graphic background (also a keyline around the image cell, adjustable for colour and width).
The sizing of the page needs a little thought, since you cannot size this in pixels directly; Print happens in real-world-units. The real-world scale affects the output sharpening and the limits on line-width etc, while the PPI controls the pixel dimensions that will export from this page.
I find it simplest to size this page not in the print setup, but in the Custom File Dimensions that you get in the Print Job panel, once you have changed this from "print to: Printer", to "print to: JPEG File".
For example, one might size the page here in inches, presuming 100ppi for ease of calculation - so a 2048 x 1224 px might require a 20.48" x 12.24" page.  Or, 10.24"  x 6.12" at 200ppi would result in the same pixel dimensions output, though this would output sharpen etc differently. It takes just a little experiment, then saving the whole thing as a a print preset which you can recall in the future whenever this same requirement comes up again.
The POINT of all this (finally - grin), is that your image is hosted on this Print page inside an image cell. And this cell does not have to be the same shape as your current crop, and in that case, "Zoom to Fill" self-crops the image on-the-fly, as an override. This second "print crop" starts out centred, but you can then drag this into the preferred composition as you want. Otherwise with Zoom to Fill unchecked, LR pads-out margins where the image does not fit the chosen shape; either way, your actual pixel output will still be the chosen width and height overall, in a standard "page" format, to contain a standard-size image cell.
This image cell can auto-rotate the picture, and then some of your resulting JPGs will require further rotation outside LR in order to show the right way round on screen. Alternatively, whole separate portrait and landscape page setups can be made, and then selectively used according to the orientation of the various pictures - you can Filter the filmstrip by picture orientation quite easily, if you have previously saved the appropriate Filter presets.
One incidental aspect of this: having selected sRGB (say), you get a choice of rendering intent.
[edit: another unavoidable aspect of this method: the original picture filename does not get used in the filename of the new, "printed" JPG. The embedded metadata does seem to report this (for example, the Copyright metadata field was preceded in a test I made earlier, with the starting file name) - but naming has to be done specially. IIRC, multiple images "printed" in this way get the filename you define, plus a sequence number.]