I'm still doing the Photo a Day with my iPhone. Here's a little peek of my desk...
I'm a big fan of both Liquitex Professional Acrylic Ink and Daler- Rowney FW Acrylic Artists Ink. They are permanent, water resistant, very fluid, and lightfast. Daler-Rowney even has a lightfast chart.
Spray inks are easily made if you are working with either Liquitex or Daler-Rowney FW brands because they are highly pigmented and can be substantially diluted with water. I typically start with a 10 parts water and 1 part ink. If that doesn't get the color I want, either add more ink or water. I used cheap spray bottles I picked up from Amazon...poof I am ready to rock some color.
The below is spray inks with brushwork on gesso.
What I like about them is that they are a quick dry and behave kinda like watercolors so they are a shinning star for mixed media work. Fabulous for art journal backgrounds too. The ink is brilliant color in a bottle..that can be used in collage, brush, on fabric, photo tinting, airbrushing, etc, etc, etc.
What I find the most useful is that they are easily mixed with acrylic paint and acrylic mediums.
Oh yeah...forgot...the photos were taken with my iPhone. I'm really serious about using my iPhone for daily photos.
Later Gators...I'm back to the studio...