Spot color printing is one of the main techniques used in screen printing, and it refers to printing specific, solid colors—usually from premixed inks—rather than using blends or gradients (like in process or CMYK printing).

Here’s a breakdown:

• A spot color is a single, pure ink color that’s printed through its own screen.
  
• Each color in the design requires its own stencil (screen) and a separate print pass.
  
• Spot colors are typically Pantone (PMS) colors, meaning they’re chosen from a standardized system so they can be matched precisely across different print jobs.

4-color process, also known as CMYK printing, is a color separation technique used in screen printing (and other printing methods) to reproduce full-color images, such as photographs or detailed graphics, using only four ink colors: Cyan, Magenta, Yellow, and Black

How It Works

1. Color Separation:
   The original image is separated into four grayscale images, one for each CMYK color.
   
   Each separation represents how much of that color is printed in each part of the image.
   
2. Halftones:
   Each color separation is converted into a halftone pattern (tiny dots of varying size and spacing).
   
   These dots overlap at specific angles to visually blend into thousands of colors when viewed from a normal distance.
   
3. Printing Order:
   Typically printed lightest to darkest: Yellow → Magenta → Cyan → Black.
   
   Precise registration between colors is critical.
   
4. Result:
   When printed together, the transparent inks combine optically to reproduce a full range of colors.
   

Key Points for Screen Printing

• Works best on white or light-colored garments since process inks are transparent.
  
• Requires high mesh count screens (e.g., 230–305 mesh) for fine halftones.
  
• Proper dot gain control, off-contact distance, and accurate registration are essential.
  
• Often used for photorealistic or full-color images rather than spot-color graphics.

Simulated process is a color-separation and printing technique used to reproduce photorealistic or highly detailed full-color images—especially when printing on dark garments.

What “Simulated Process” Means

Simulated process uses spot colors (usually plastisol inks) arranged in halftone dots to recreate complex images that look like full-color prints.

It simulates full-color process printing (CMYK), but is more versatile and produces better results on dark fabrics.

How It Works

1. Artwork Separation
   The original image is separated into several spot-color channels.
   
   Each channel represents a specific ink (e.g., highlights, mid-tones, shadows, warm tones, cool tones).
   
   Halftones are used so colors visually blend on the shirt.
   
2. Screen Creation
   Each color channel gets its own screen.
   
   Screens are prepared with different halftone patterns and dot sizes.
   
3. Printing
   Typically 6–10 screens are used.
   
   Lighter colors are printed first on top of a white underbase.
   
   Colors are layered carefully so the halftones blend into a full-color image.
   
4. Final Effect
   -Smooth gradients
   -High detail
   -Photographic look
   -Works well on dark shirts

When Simulated Process Is Used

• Complex illustrations
  
• Photographic images
  
• T-shirts with gradients, flames, animals, people, etc.
  
• Any detailed artwork requiring many tones

Stretch additives and 3D additives are special chemical modifiers mixed into ink to change how the ink behaves or looks on fabric (or other substrates). Here's what each one does:

Stretch Additives (a.k.a. Stretch Bases / Elastomers)

Purpose:
To make plastisol or water-based inks more elastic so they can stretch with flexible fabrics without cracking.

Why it’s used:

• Printing on spandex, Lycra, athletic wear, yoga wear, leggings, swimwear
  
• Prevents ink from cracking when the fabric stretches
  
• Improves soft hand feel on stretchy garments
  

How it works:
The additive usually contains elastic resins or plasticizers that increase the ink’s elongation properties. You mix a certain percentage (often 5–20%) into your ink.

3D Additives (a.k.a. Puff Additives / High-Density Additives)

Purpose:
To create raised, textured, or three-dimensional effects in screen printing.

Types of 3D additives:

1. Puff Additive

• Expands when heated in the dryer
  
• Creates a foamy, puffy, raised look
  
• Great for vintage or bubbly textures
  

2. High-Density Additive

• Makes ink thicker so it can be printed in tall, sharp-edged layers
  
• Used for high-density prints, similar to rubbery 3D logos
  

3. Silicone-Based 3D Additives

• Create super-elastic, glossy raised surfaces
  
• Used a lot in sportswear and high-end fashion prints
  

Why it’s used:

• To get a 3D, tactile finish
  
• To enhance logos, lettering, or decorative elements