When using the Brush tool in Photoshop, it may seem that adjusting flow and opacity sliders will do exactly the same thing. But of course, they wouldn’t both be there if they were exactly the same, right? In this tutorial, Matt Kloskowski explains the difference between the two and shows you how they work on his own example.
Although the difference between flow and opacity is subtle, you’ll spot it when you use one after the other. Matt draws with a black brush on the white background to demonstrate how each tool works. Basically, when you reduce the opacity and start drawing while holding the click, the intensity of black will remain the same no matter how many times you go over the same spot. Only when you release the mouse, click again and start drawing, the amount of color will start to build up. It’s different when you reduce the flow. When you click the mouse and start drawing, the color will build up every time you paint over the same spot, even if you don’t release the click.
Of course, there’s no rule when to use one and when the other. You can even combine them if you like. But, working with flow gives you a little more control and it can be more intuitive and natural. On the other hand, working with reduced opacity could come in handy when you want a bit less subtle changes. It all depends on your preferences and what you want to achieve.
Matt illustrates both options nicely as he blends two photos together in Photoshop. So, make sure to watch his video to get a better idea of how these tools work, so you can make the best of both.