I had a request in recently on the best way to increase the size of a Photograph for a poster. Luckily Photoshop CC has the new Up Sampling algorithm to help me out.
There have been many strategies for up sampling/up resing an image in the past, do you do it in one go, do you do it in increments of 50%, but which ever way there is alway some confusion to the best one to use on a real world image.
Photoshop CC was released with a brand new Intelligent Up Sampling Algorithm that has been designed to do this exact operation, but keeping it really simple. One of the elements that photographers worry about is sharpness and that if an image is increased in size it will loose some of the edge sharpening. The new up-sampling code in Photoshop CC has been designed to not only make the up-sampling super easy, but will also intelligently protect the edges during the operation.
Let us work with an example.
This will will be sent to Photoshop CC, either by pressing CMD+E (Mac) or CTRL+E on a PC, or by opening at as a Smart Object in Photoshop CC. You can see that the image size is 4624h x 3468w, or big enough to print (out of the box) at just over 9 x 12, but lets be honest, we could probably print this as is at 18 x 24 and there would be no significant loss of quality.
N.B. From a performance point of view, there is a significant difference in processing an image that is brought into Photoshop CC as a Smart Object compared to opening the file in the traditional way (or not as a Smart Object).
But anyway, say, that i wanted to upscale this to A0 or larger.
Inside Photoshop, the usual way to increase the size is to open the menu option Image / Image Size. Then decide on the new size and just type it into the boxes. You can see below, that i am increasing the size to 42inches on the height, which happens to be 326% of the original size. Notice, that the “resample” check box is turned on and the “Preserve Details (enlargement)” option has been selected. This option will use the new intelligent up sample code and protect the edges. Also, notice that if any noise is generated during the process, you can adjust the “Reduce Noise” slider to reduce it.
Once the conversion has completed i have zoomed into 100% and provide a couple of screen shots. You can clearly see that Photoshop CC has done an incredible job of protecting the edges even when increased to over 300% the original size.
A second shot of the new up-sampled image.
N.B Up-sampling to this sort of size will increase the file size. In this example it has increased from just under 92mb to just over 980mb.