How can I darken PDFs for printing from iPad

My piano teacher sometimes sends me scans done with her phone when we have a Zoom lesson. These come to me as PDFs attached to email or messages to my iPad Air or iPhone. Something changed and now the attachments are very pale on screen and in print. I try to print these on my HP Envy 6055e, but they are light, hard to read. I thought there would be an option to print darker in the HP Smart Print app, but the app is pretty stupid. I get an option in Print paper type>Quality>Best, but best doesn’t do anything to darken. I asked this question on HP support community but only got a suggestion to set the quality to best. https://h30434.www3.hp.com/t5/Mobile-Printing-Cloud-Printing/Get-darker-print-from-HP6055e/td-p/8206038.

I thought of finding an app for iOS that would let me darken the PDF before printing. “PDF Expert “ looked promising, but didn’t darken PDFs.