What are the differences between sRGB Adobe RGB and ProPhoto RGB and which is best for sharing online

I’m getting really confused about color spaces! I’m a hobbyist photographer, mostly taking pictures of landscapes and portraits. I’ve noticed the settings in my camera (a Sony a7iii) for color space: sRGB, Adobe RGB. I’ve also heard of ProPhoto RGB, but I don’t even see that as an option in my camera.

I’m trying to understand what the actual differences are between these color spaces in a way that’s easy to grasp. I know they have different gamuts, but what does that really mean in practical terms? Does one look "better" than the others? Will my photos look dull if I choose the "wrong" one?

And most importantly, which of these should I be using when I ultimately want to share my photos online (Instagram, Facebook, my website, etc.)? I’ve heard conflicting advice, and I want to make sure my photos look their best when viewed on different devices. Is one definitively the best choice for web sharing, or does it depend on something else? Should I be converting them to a certain color space before uploading?

I’d really appreciate a clear explanation aimed at someone who isn’t a color science expert!

Answer

sRGB, Adobe RGB, and ProPhoto RGB are three different color spaces, each defining a specific range (or gamut) of colors that can be represented. They differ significantly in their size, intended use, and suitability for various workflows. Here’s a breakdown of their differences and which is best for online sharing:

1. sRGB (Standard Red Green Blue):

• Gamut Size: The smallest of the three color spaces.
• Origin: Developed by Hewlett-Packard and Microsoft in 1996 to standardize color representation on monitors and the internet.
• Characteristics: Represents approximately 36% of the colors visible to the human eye (as defined by the CIE 1931 color space). It omits many saturated colors, especially greens and cyans.
• Use Cases:
  • Web Browsers: All major web browsers are designed to display images in sRGB.
  • Most Monitors and Displays: Most consumer-grade monitors, laptops, smartphones, and tablets are calibrated to approximate the sRGB color space.
  • Online Sharing: The standard for images displayed on the internet.
  • Consumer Printing: Many consumer-level printers and print labs assume sRGB input.
  • Gaming: Primarily used in video games.
• Advantages:
  • Compatibility: Ensures consistent color appearance across a wide range of devices and platforms without the need for color management.
  • Small File Size: Smaller gamut often translates to smaller file sizes.
• Disadvantages:
  • Limited Color Range: Cannot accurately reproduce many vibrant colors.
  • Color Clipping: Can lead to a loss of color detail in highly saturated images if the original image contained colors outside the sRGB gamut.

2. Adobe RGB (1998):

• Gamut Size: Larger than sRGB.
• Origin: Developed by Adobe Systems in 1998 to encompass more of the colors reproducible in CMYK printing.
• Characteristics: Represents approximately 50% of the colors visible to the human eye. Includes a significantly wider range of greens and cyans compared to sRGB.
• Use Cases:
  • Professional Photography: Used during editing, especially when vibrant colors need to be accurately represented.
  • Print Production: Suitable for preparing images for printing, as it can represent more colors achievable in print (although CMYK has its own limitations).
  • High-End Monitors: High-quality monitors designed for graphic design and photography often support close to 100% Adobe RGB coverage.
• Advantages:
  • Wider Color Range: Captures and reproduces more saturated colors.
  • Better for Editing: Provides more color information to work with during post-processing.
• Disadvantages:
  • Inconsistent Display on sRGB Devices: Colors may appear dull or muted on devices and browsers that do not support color management and are calibrated to sRGB.
  • Requires Color Management: Requires color profiles and color-aware applications to ensure accurate color reproduction.

3. ProPhoto RGB (ROMM RGB):

• Gamut Size: The largest of the three color spaces, encompassing virtually all colors that a camera can capture.
• Origin: Developed by Kodak.
• Characteristics: Contains approximately 90% of the colors visible to the human eye. Includes many imaginary colors (colors that cannot physically exist), which are used for mathematical calculations during image processing.
• Use Cases:
  • Professional Image Editing: Ideal for maintaining maximum color information throughout the editing process, especially when performing extensive color corrections or manipulations.
  • Archiving: Suitable for archiving images to preserve the widest possible color range for future use.
• Advantages:
  • Extensive Color Range: Minimizes the risk of color clipping during editing.
  • Greater Flexibility: Provides more flexibility for color adjustments without losing color information.
• Disadvantages:
  • Limited Display Capability: Most monitors cannot display the full ProPhoto RGB gamut.
  • Large File Sizes: Can result in larger file sizes due to the increased color information.
  • Requires Color Management: Absolutely requires color management to avoid unpredictable color shifts.
  • Not Suitable for Direct Display: Not intended for direct viewing on most devices or for web use.

Which is Best for Sharing Online?

sRGB is the best color space for sharing images online.

• Compatibility: Web browsers and most online platforms are designed to display images in sRGB. Images saved in Adobe RGB or ProPhoto RGB may appear dull, desaturated, or with incorrect colors on devices that are not color-managed or are calibrated to sRGB.
• Consistency: Using sRGB ensures that your images will look as consistent as possible across different devices and browsers, providing a better viewing experience for your audience.
• Simplicity: It eliminates the need for viewers to have color-managed systems to see your images correctly.
• File Size: sRGB images are generally smaller in file size, which is beneficial for faster loading times on websites and social media.

Workflow Recommendations:

1. Shoot in RAW: If possible, shoot in RAW format. This captures the most color information possible from your camera’s sensor.
2. Edit in a Wider Gamut (Adobe RGB or ProPhoto RGB): During editing, work in Adobe RGB or, for the most flexibility, ProPhoto RGB. This allows you to make extensive color adjustments without clipping or losing color information.
3. Convert to sRGB for Output: Before sharing your images online, convert them to sRGB. This ensures compatibility and consistent color appearance across different devices and platforms. When converting, use a perceptual rendering intent to maintain the visual appearance of the colors as closely as possible.