Here is a primer for the basic generation parameters.
Classifier Free Guidance scale is a parameter to control how much the model should respect your prompt.
1-Mostly ignore your prompt
3-Be more creative
7-A good balance between following the prompt and freedom
15-Adhere more o prompt
30-Strictly follow the prompt
Below are a few examples of increasing the CFG scale with the same random seed. In general, you should stay away from the two extremes - 1 and 30.
Recommendation: Starts with 7. (Increase if you want it to follow your prompt more)
Quality improves as the sampling step increases. Typically, 20 steps with Euler sampler are enough to reach a high quality, sharp image. Although the image will still change subtly when stepping through to higher values, it will become different but not necessarily higher quality.
Recommendation: 20
There is a variety of sampling methods you can choose, depending on what GUI you are using. They are different methods for solving diffusion equations. They are supposed to give the same result but could be slightly different due numerical bias. The only criteria is the image looks good, accuracy of the method should not be your concern.
Not all methods are created equal. Below are the processing time of various methods.
Recommendation: Euler
The random seed determines the initial noise pattern and hence the final image.
Setting it to -1 means using a random one every time. It is useful when you want to generate new images. On the other hand, fixing it would result in the same images in each new generation.
Recommendation: Set to -1 to explore. Fix to a value for fine-tuning.
The size of output image. Since Stable Diffusion is trained with 512×512 images [Warning: may out of date], setting it to portrait or landscape sizes can create unexpected issues. Leave it as square whenever possible.
Recommendation: Set image size as 512×512.
Batch size is the number of images generated each time. Since the final images are very dependent on the random seed, it is always a good idea to generate a few images at a time. This way, you can get a good sense of what the current prompt can do.
Recommendation: Set batch size to 4 or 8.
Stable Diffusion is that it often has issues with faces and eyes. Restore faces is a post-processing method applied to images using AI trained specifically to correct faces.
Recommendation: Turn restore faces on when you generate images with faces.
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