Resize and adjust resolution

[pecheurs]

This shouldn't be a complex matter but finding it is. I simply want to adjust the size of an image and change the resolution. I am to crop an image down to 3250pixels x 2500pixels and adjust the resoluiton to 275. This is for a PSA competition. I have the CC version of everthing but the tutorials head off in specific directions which this new user gets easily confused and bored. 

[ManiacJoe]

Cropping is about the shape of the image (4x6, 8x10, 5x7). This is done using the crop tool in the Develop module.

Resizing (changing the pixel dimensions) is done during the "export" process. Enter the desired size of the box you want the exported image to fit into.

Resolution is about the pixels per inch during the printing process. If you are not printing, the number is meaningless. If you are printing, the number is the first one discarded and recalculated by the printing software. However, you are allowed to include the number in the "export" process.

[pecheurs]

Yes, I understand the basics of cropping but cropping to a specific size is the question. Once done, setting the resolution should be a snap. Both boxes are not in the desktop/CC version…the one pictured in the Classic tutorials and elsewhere online. So…where has this box gone? Regardless, issue remains.

[kimballisms]

With the image selected in Lightroom, hit the R key.  This will enter the cropping tool.

The cropping tool options are in the upper right of your screen, with the rest of the develop panels.  Activate the drop-down menu of crop aspect ratios.  Click "Enter Custom..." in the menu.

Enter your given pixel requirements exactly as if they were an aspect ratio-- you don't need to reduce the fraction, but just know that LR will treat it as a ratio.  Make sure the aspect ratio "lock" is on, and resize/place your crop boundary as desired.  Hit enter to finish.  Note you've only cropped the image to the correct aspect ratio, not actually resized it.

When exporting the image, make sure you've selected the appropriate resize settings to get the exact pixel width/height and DPI you need.  As others have said, DPI is pretty pointless.

Enjoy!

[JP Hess]

it is only possible to crop to a specific ratio in Lightroom Classic using the crop tool. To have an image of specific dimensions and resolution is controlled using the export function. Therefore, you would first crop the image to a ratio using the crop tool. Then it would be necessary to export a new image that would have the specific dimensions and pixel density that you require.

[GoldingD]

Please verify your Lightroom version, as Lightroom reports it. Click on Help, then System Info, then Copy. Paste first 12 lines into a reply.

[pecheurs]

Lightroom version: 3.1 [ 20191126-2330-434c343 ] (Nov 27 2019)
NGL Version: 1.11.0.8
Operating system: macOS
OS Version: 10.15 [1]
Application architecture: x64
Computer model: iMac14,1 / Intel(R) Core(TM) i5-4570R CPU @ 2.70GHz
Logical processor count: 4
Processor speed: 2.7 GHz
Built-in memory: 8,192.0 MB
Real memory available to Lightroom: 8,192.0 MB
Real memory used by Lightroom: 847.5 MB (10.3%)
Virtual memory used by Lightroom: 1,747.6 MB
Memory cache size: 387.7 MB
Internal Camera Raw version: 12.1 [ 351 ]
Maximum thread count used by Camera Raw: 3
Camera Raw SIMD optimization: SSE2,AVX,AVX2
Camera Raw virtual memory: 309MB / 4095MB (7%)
Camera Raw real memory: 310MB / 8192MB (3%)
Displays: 1) 1920x1080

[GoldingD]

Yep, suspected as much. You can blame this on the hideous marketing decisions by Adobe. They really fouled up on product names.

[JP Hess]

Now perhaps we understand some of your confusion. You asked your question in the Lightroom Classic forum, and you are using Lightroom. There is a big difference in the export options. Lightroom doesn't have nearly as many options available. If you choose Custom then you can specify how many pixels are needed on the long side of an image that you are exporting. You calculate how large the image needs to be. If the image is a landscape image that is going to be printed 8 x 10" and you want it printed at 300 PPI then the long edge needs to be 3000 pixels. This would be after you have cropped the image to a 4 x 5/8 x 10 crop ratio. You would export the image, and that copy would be the image you would use.

Changing the resolution setting in the file literally has no impact on the quality of an image. It is simply a reference setting. An image that is set at 72 PPI will produce precisely the same results as an image set at 300 PPI because the pixel dimensions are the same. Try printing the same size print from an image saved at both resolution settings, and you will discover that there will be no difference in print quality.