Caught more than once without supplies when inspiration struck? You may want to keep a mini art bag in your purse or briefcase so you can capture whatever catches your eye. An iPhone camera works as a last resort, but working directly with art supplies is usually best.
A sketch pencil bag, available at any chain craft store, is inexpensive and stores pencils, slim colored markers, a tortillon, an eraser, pencil sharpener, a few watercolor pencils, a small vial of water (one of the few positives from TSA regulations) and several different sizes of artist trading cards. A small, spiral bound sketch pad adds little weight and all together, weighs less than a pound.
The case has a convenient loop on one end which is great for attaching to a jump ring and then to your purse or belt or the spiral binding of your sketch pad. The sketch book (3”x5”) will fit in a back pocket or purse easily too. If you like, you can adhere a small pocket (think library due date card size) to the back cover of the sketchbook for small ephemera from the day. A few small sheets of wax paper in the back protect pages from sticking together, particularly important if you are making a wet or sticky surface.
In the front of the sketch book, make samples of the markings of each of the pencils, markers, and watercolors or other supplies that you are carrying. Then note beneath them which one it was. This way, you can choose just the right color or texture.
Depending on what type of day it is, i.e.: work day, weekend, unexpected day off, you will never be caught without what you need. Preparation is 90 percent of the fun. Sometimes, I keep a kit in the car and at my desk at work for those ten or fifteen minute art retreats. Even if the retreat is between my ears.
Do be careful what you leave in a hot car though. Crayons, pastels and even some paints will separate or melt in extreme temperatures. When it doubt, take it out.
Whatever your medium of choice, remember that the purpose is not Louvre-quality art, it is to record inspiration at the time it hits. Always you have the option of a dual inspiration shot – one digital image and one drawn. If you forget a part of the scene it is easily recreated.
Have fun with it!