Check the edition and mod loader first
Iris is designed for Minecraft Java Edition. Its official website lists support for Fabric and NeoForge in their respective versions; Forge is not supported. Don't mix up the names of similar loaders. On the download page, select an option for your game profile. Before making changes, save your current components and make sure the game runs normally.
Iris and the shader pack do different things
Iris provides the shaders, and a separate package sets the selected appearance. The official Iris build includes Sodium. Get the loader through the developer's links, then check the requirements of the selected package. The presence of Iris in a profile does not in itself mean that the desired effects are already enabled. After installation, check the availability of package management in the graphical settings.
Where to start checking an image
Turn on one compatible package and compare the same part of the world before and after. Look at the lighting, water and visibility of objects, then check the smoothness of the movement. For comparison, keep the location and drawing distance the same. If performance decreases, reduce the package parameters and repeat the same route. The author's beautiful photo does not show how the package will work on your device.
How to look for conflict
The developer of Iris warns of incompatibility with OptiFine, Canvas and some rendering mods. If the game stops starting, return the minimum profile and connect components one at a time. For a specific package error, write down its name, Iris version, and device characteristics. Some combinations with other visual mods require explicit package support. Testing one change at a time helps differentiate startup failure from poor performance.
Sources and checks
Guides are automatically translated from Russian; interface labels may differ. The Russian edition is the original.