Fixing JPEG’s “Photocopier Effect” or Generation Loss Problem

Summary: The quality of JPEG files deteriorate when you make copies of the original file. This blog suggests some methods by which you can fix the JPEG ‘Photocopier Effect’ problem and prevent ‘generation loss’.

?Photocopier Effect? is the process of copying files such as copies of documents and images with a slight difference in the quality of the copies files. For instance, when you open a JPEG file on an image editor application and save it, the saved file will be different than the original one.

What is generation loss?

Copying JPEG/JPG files might result in ?generation loss? as it deteriorates quality and resolution. Making a copy of file results in the reduction of quality in subsequent copies of JPEG files and it is known as ?Generation loss?. JPEG is a lossy image format and sometimes behaves like photocopiers; hence the name ?Photocopier Effect?.

When a JPEG file is copied, then the resultant files should be identical to the original JPEG files but that is not the case and you have to fix the ?JPEG Photocopier effect? in order to get the same resolution. When you upload a JPEG file on a social media platform, the pictures are re-encoded to use relatively lower bandwidth and size; thus, reducing the quality of the pictures.

Figure 1: Illustrates a picture with ?Generation Loss?

 The Reason behind JPEG Photocopier Effect

JPEG files are represented as pixels using color space transformation i.e. 8-bit RGB (Red, Green, Blue). Each of the colors has 256 different levels of intensity which results in a myriad of permutations and combinations of these defined colors. But when it comes to image compression, JPEG uses ?YCbCr? or YUV-type imaging where Y refers to the intensity of light and U, V refers to color components. For instance, in a grayscale image, JPEG uses a YUV color channel.

Although this color transformation has an advantage i.e. human eye is more sensitive to Y (intensity of light) than it is to the color component yet it results in some loss. If you transform JPEG files from RGB to YCbCr or vice versa, then the number of different color combinations would be different. Further, converting RAW to uncompressed RGB doubles or even triples the amount of data to record. Besides, RGB requires high bandwidth for transmission and storage space.

Figure 2: Illustrates a significant change in color after converting to YCbCr and back to RGB

 It is not like only JPEG files suffer from generation loss, modern image file formats such as BPG or WebP also suffer from the loss. Read more on Complete List of JPEG Errors & Their Solutions

How to fix JPEG?s Photocopier Effect

Implement these procedures to fix JPEG Photocopier Effect.

Tip: Tough generation loss can easily accumulate if an image goes viral and it jumps frequently between those different websites. For this reason, using ?Share? or ?Retweet? is better than downloading the image and then re-uploading it.

What about other image formats?

JPEG file format is one of the oldest & most used file formats available in the market. Though, there are other popular formats launched in market like WebP & BPG but they suffer more from generation loss.

The reason for this is that JPEG does everything in 8×8 blocks of pixels and most of the error accumulation cannot cross the boundaries of these macroblocks. The more modern formats WebP and BPG use variable-sized, larger macroblocks, which is good for compression, but it also means that an error in one part of the image can more easily generate to other parts of the image.

Tips: To save JPEG from Generation loss while editing-

·         Do not fully re-encode the JPEG file if you just need to crop or rotate the image.

·         If your editing is more related to pixels, always use the higher quality setting for scaling down, rotating by an arbitrary angle, or applying some kind of global filter or effect.

Read the below Steps to know how the software works:

  1. Click on ?Add File? located in the middle of the home screen to repair corrupt or damaged JPEG files
  2. Select the files that you wish to repair. Moreover, click on ?Add/Remove? to add or remove any file    
  3. After selecting the files, click on ?Repair? to proceed with the repairing process and once it is complete, preview the repaired JPE files and save them at the preferred location

Conclusion

So, these are some easy and effective procedures to fix the JPEG Photocopier effect. Overall, if you?re still not able to fix the issue, then you can leverage Stellar Repair for Photo and repair corrupt and damaged JPEG files. Above all, keep a backup of all your files.

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