L3: Latent Upscaling in ComfyUI - Comfy Academy

Olivio Sarikas
15 Jan 202409:24

TLDRIn this workshop segment, the presenter delves into the concept of latent images and their application in AI, particularly focusing on the K-Sampler. The tutorial guides users through a workflow that leverages latent points to create a variety of artistic expressions. It highlights the importance of upscaling images for better detail and introduces techniques to enhance image quality, such as adjusting the D-noise and experimenting with different samplers. The session encourages hands-on exploration and emphasizes the value of testing and refining the process to achieve desired outcomes.


  • 🎨 The latent image is a concept in AI art where pixels are encoded into latent points for AI processing.
  • 🖌️ The AI cannot directly work with pixels, so a conversion to a latent image is necessary for artistic expression.
  • 📚 The workshop provides a workflow for using AI in art creation, available for download on Open Art.
  • 🌐 The Lounge workflow allows users to run the workflow in the cloud for free without downloading or installing anything.
  • 👤 The basic text-to-image workflow involves loading a checkpoint, inputting text prompts, and using a case sampler to generate an image.
  • 🔍 The VAE (Variational Autoencoder) is optional but can improve results depending on the model used.
  • 📸 Upscaling is necessary for images with smaller details to maintain quality and avoid deformation.
  • 🛠️ The 'upscale latent by' node multiplies the width and height of the latent image, simplifying the process.
  • 🎭 The second case sampler allows for additional positive and negative prompts to influence the final image.
  • 🔄 Experimenting with different samplers and upscaling methods can lead to varied and improved image results.
  • 🚀 Using an initial upscaling step before the ultimate upscaler can enhance image quality, especially when starting with low-resolution images.

Q & A

  • What is the main topic of the workshop?

    -The main topic of the workshop is about the latent image and specifically the latent input into the K sampler in AI.

  • How can one access the presenter's workflow?

    -The presenter's workflow can be accessed by downloading it from Open Art, where there is a download button available.

  • What does the term 'latent image' refer to in the context of AI?

    -In the context of AI, a 'latent image' refers to the encoded representation of pixels, which are transformed into latent points that the AI can process, rather than the actual image itself.

  • Why can't AI directly deal with pixels?

    -AI cannot directly deal with pixels because it requires a different kind of format. Pixels are encoded into latent points for AI to process them effectively.

  • What is the purpose of the VAE (Variational Autoencoder) in the workflow?

    -The VAE (Variational Autoencoder) is used to encode the pixels into latent points and can be chosen differently based on the model for better performance.

  • How does the presenter address low-resolution issues in AI-generated images?

    -The presenter addresses low-resolution issues by upscaling the image. This involves increasing the resolution and using a higher D noise value to avoid fragments in the rendered image.

  • What is the function of the 'View Q' in the workflow?

    -The 'View Q' function allows users to preview the image while it's being rendered. If the user is not satisfied with the preview, they can cancel the rendering to save time and GPU power.

  • Why is it recommended to try different Samplers?

    -Trying different Samplers is recommended because it can yield better image results. Different Samplers can introduce variations that enhance the quality and detail of the upscaled image.

  • What is the significance of the 'upscale latent by' node in the process?

    -The 'upscale latent by' node is significant as it multiplies the width and height of the latent image, allowing the user to easily control the size of the upscaled image without having to specify exact dimensions.

  • How does the presenter suggest improving the quality of the upscaled image?

    -The presenter suggests using the 'upscale latent by' node first to increase the image size and then using the ultimate upscaler with a low D noise value to stick as close as possible to the original image details.

  • What is the purpose of creating probes within the workflow?

    -Creating probes within the workflow allows users to check the process at any stage, providing a preview of what is happening. This helps to ensure that the process is working correctly and yielding the desired results.



🎨 Introduction to Latent Image and AI Art Workflow

This paragraph introduces the concept of the latent image in AI art creation, emphasizing its simplicity and potential for artistic expression. It guides the audience through a workshop where they can download a workflow on Open Art and run it in the cloud for free. The explanation focuses on how pixels are encoded into latent points, which AI can process, rather than dealing with pixels directly. The paragraph also revisits a basic text-to-image workflow, discussing the use of a VAE (Variational Autoencoder) for different models and the importance of resolution in achieving detailed images. It touches on the process of upscaling images for better detail and sets the stage for further exploration of the latent image in AI.


🔍 Enhancing Image Resolution and Upscaling Techniques

The second paragraph delves into the process of enhancing image resolution using the latent image workflow. It explains how to upscale images by adjusting the latent points and using different upscaling methods. The paragraph highlights the importance of setting the right D noise level to avoid blocky or noisy images. It also encourages experimentation with various samplers to achieve better image quality. The speaker demonstrates the impact of upscaling on image sharpness and detail, especially for faces, and suggests using an initial upscaling step before applying the ultimate upscaler for improved image quality. The paragraph concludes with a call to action for viewers to explore more about latent input in upcoming workshop videos.



💡latent image

The term 'latent image' refers to a representation of an image that is not immediately visible but is encoded in a form that can be processed by AI systems. In the context of the video, it is a pile of latent points that are derived from the original pixels of an image. These points are used as input for AI models, which cannot directly work with pixels, allowing for a variety of artistic expressions and image generation.

💡K sampler

The 'K sampler' is a component in AI workflows that uses the latent image to generate a final image. It is a crucial part of the process that transforms the latent points into a visual output. The video emphasizes the simplicity and versatility of using a K sampler, which can produce a wide range of artistic results from a single input.


A 'workflow' in the context of the video refers to a series of steps or processes used to accomplish a specific task, such as generating images with AI. The speaker provides a workflow that can be downloaded and used by the audience, which includes various components like the K sampler and VAE (Variational Autoencoder).

💡VAE (Variational Autoencoder)

VAE, or Variational Autoencoder, is a type of neural network used for unsupervised learning of complex data. In the video, it is used to help encode and decode images into and from latent points, playing a key role in the generation of images from the latent image.


To 'upscale' an image refers to the process of increasing its resolution or size. In the video, upscaling is necessary when the original image generated by the AI model is of low resolution and lacks detail. The speaker describes techniques for upscaling images to improve their quality and detail.

💡D noise

In the context of the video, 'D noise' refers to a parameter used in the upscaling process to control the level of noise or blockiness in the resulting image. A higher D noise value can help to avoid fragmented or blocky images, but it may also alter some details of the original image.


A 'preview' in this context is a low-resolution or quick version of the image that is generated before the final output. It allows the user to assess the quality and direction of the image generation process, making adjustments as needed before committing to the full rendering.

💡GPU power

GPU, or Graphics Processing Unit, power refers to the computational capacity of the GPU, which is particularly important in AI and image processing tasks due to their heavy computational demands. In the video, the speaker discusses optimizing GPU usage by disabling certain parts of the workflow when not needed.


The term 'text-to-image' describes the process of generating visual images from textual descriptions. This is a core theme of the video, where the speaker guides the audience through an AI workflow that takes text prompts and transforms them into images using latent points and a K sampler.

💡ultimate upscaler

The 'ultimate upscaler' is a term used in the video to describe a tool or method for significantly increasing the resolution of an image. It is used after an initial upscaling step to achieve the desired final size and quality of the image.


The workshop focuses on using the latent image with AI for artistic expression.

A latent image is not an actual image but a collection of latent points, which are encoded from pixels.

The presenter shares a workflow on Open Art, which can be accessed and run in the cloud for free.

The basic workflow involves text to image conversion using a checkpoint and text prompts.

A VAE (Variational Autoencoder) is used to enhance the image quality, especially for high-resolution images.

Upscaling the image is necessary for better detail, especially when the subject is smaller in the image.

The presenter explains how to disable background rendering to save GPU power.

The process of upscaling involves using an 'upscale latent by' node and a second CAS sampler.

Different upscaling methods and samplers can be experimented with to achieve desired image quality.

The presenter demonstrates how to use a preview function to cancel unwanted images during rendering, saving time and resources.

The use of D noise helps in managing the quality of the upscaled image, avoiding blockiness or noise.

The presenter suggests using the ultimate upscaler with a low D noise value for the final image to stick close to the original.

The workshop provides practical tips on improving image quality through the manipulation of latent images in AI.

The presenter invites the audience to explore the potential of latent input for artistic creation in AI.

The workshop concludes with an encouragement to watch the next videos for deeper insights into working with latent input.

The end screen offers additional resources and encourages viewers to like and share for more content.