How to Compress Pictures
Our digital cameras, and yes, even our smartphones, capture high resolution images with file sizes often in the double-digit megabyte range. And we want that. Those millions of pixels allow us to display our photographs on large monitors, make big prints, and crop out portions of the photo and still have enough visual information for a crisp image.
But there are instances when we want to compress those files to take up less space on our storage devices, or to make them easier to send to others electronically. In those situations, you can make compressed copies of your files in Luminar, following these steps.
Once you've finished editing in the Luminar standalone application, go to File > Export. You'll be greeted with a dialog box displaying five file options for changing the file characteristics, plus the ability to create a name for the image and choose the location for saving it.
When choosing the name, I recommend that you indicate that this is a compressed file by adding a word such as, "web" or "share". This will help you quickly distinguish your compressed files from the masters.
Now let's take a look at the lower part of the dialog box. The first option is for sharpening. Generally speaking, when we resample an image, that is, make it bigger or smaller than its original size, there is some loss of sharpness. By adding a little sharpening during the resampling process, we can offset that loss and maintain the integrity of the photograph. I recommend using Low or Medium for output sharpening.
When you click on the Resize popup menu, four options appear: Original, Long Edge, Short Edge, and Dimensions. Choosing Original keeps the current dimensions of the image. Generally speaking, if you want the file size smaller, you should change the dimensions so they are smaller. So Original is an unlikely option for this task.
Long Edge and Short Edge are the most common choices. For example, you can make your image no bigger than 1600 pixels on the longest or shortest side, and Luminar will reduce the entire image accordingly.
Dimensions can be helpful if you know the exact size you want the compressed image to be. If that's the case, enter the values for both sides.
This isn't related to compression per se, but if you know the final destination for your photo, choose the appropriate color space. For electronic display, select sRGB. For printing choose Adobe RGB or ProPhoto RGB.
The Format popup menu presents no less than seven options. For this project, choose Jpeg. It is the most common compressed format. And it can be opened on practically any device or with any software that supports images.
On this scale, the lower the quality setting, the smaller the file size. Photographers try to find the perfect balance between fewer bytes and acceptable image display. I recommend that you set quality between the halfway point and the 3/4 point on the scale. This will still give you plenty of compression without degrading the quality of its appearance.
Once you've made your selections, click the Save button. A compressed copy of your file will be placed in the location you set in the dialog box. In the case of our floating speaker photo, we went from a 47.8 MB Tiff file all the way down to 219 KBs for the compressed copy.