Preparing PPI for printing

[Oberious]

Is there a newer way to increase InDesign ppi to 300 without using transparency flattening and the X-1 2001 preset?

The link below shows the transparency flattening technique. 

https://indesignsecrets.com/raise-image-resolution-directly-in-indesign.php

[rob day · Accepted solution]

No. Placed images have an Actual Resolution—the resolution at 100%, and an Effective Resolution—the scaled or output resolution. If you scale an image with an Actual Resolution of 100ppi to 50%, its Effective output resolution would be 200ppi, because the scaled pixels are twice as small. With InDesign documents scaling is the only option, there is no image sampling up or down. On an export to PDF you do have an option to down sample the Effective resolution, but there’s no upsampling.

It is generally accepted that upsampling does not improve image quality in any meaningful way—the higher resolution has to be captured at input by either a camera or scanner—so InDesign has no upsampling option. The InDesign Secrets trick does increase resolution via a Flattener Preset, but would not actually improve quality. The post is over 10 years old.