Radical Impressionist: A Mathematician Paints

 In my quest to learn everything about how we can use an iPhone effectively when setting up for a Plein Air Session, I learned a lot. I hope what I have learned can be as helpful to my readers as it has been for me. I wrote this post while staying in San Diego near my son's house in Jan 2023. I took the photo of the view from the back patio.  I just read through the post (Jun 11) and rather then try to perfect it, I think it has enough useful information to publish the post.  June 11, 2023: originally published, republished Jan 31, 2026. iPhone Editing/Cropping and Aspect Ratios Tip #1. iPhones automatically take photos at a 9x12 (horizontal) or a 12x9 (vertical) ratio by default but it can be changed (see tip #2).  For the WISE Apps' Dynamic Symmetry grids described below use the 3 to 4 OR the 2 to 3 ratio OR a Golden ratio. I  have tried to edit a photo to my desired measurements incorrectly.  This leads me to .. Tip #2. The edit/crop tool provides a set ...

A Simple free Tool for your iPhone for overlaying a grid on your photo or your painting,  You don't have to use Photoshop!! All the information is here:  https://www.wikihow.com/Overlay-Pictures-on-iPhone . Or go to the app store and download the Snapseed app (free). Basic Steps with an Example  See Detailed Steps below.  Snapseed app, load an image. or take a photo to be overlayed.  In this example I selected a photo previously cropped to a 3:4 aspect ratio (9x12),   Then in the double exposure option in the app I add a 3x4 Dynamic Symmetry++ grid, pulled from my albums.  3. Resulting combined image with grid superimposed. I did adjust the opacity of the grid layer in the app (see details below).  Now, one can sketch this directly on a 3x4 "gridded" card as a study or 9x12 "gridded" canvas. Refer to the post on a detailed application in the field. Detailed Steps with the same Example: Detailed steps in the Snapseed app, applying the simple D...