When i click image at that time Raw format doesn't contain any noise, but when i opened into Adobe Photosho CC 2017 version and after modifying raw data and open to ps ans save as jpg gives colors noise.

why happening this ? is there any raw editor better than PS ?

  • 1
    \$\begingroup\$ How do you know your RAW image "doesn't contain any noise"? I think you're misunderstanding / misinterpreting something here. \$\endgroup\$
    – Philip Kendall
    Commented Jun 14, 2017 at 8:01
  • \$\begingroup\$ RAW always contains noise. It's impossible to avoid this, even though it's often at a very low level. JPEGs are made from RAW data and generally will have noise reduction applied. You probably need to adjust the amount of noise reduction in PS (which you can control) and normally I'd apply a lot more chroma (color) noise reduction than luminance noise reduction, as this helps keep detail. \$\endgroup\$ Commented Jun 14, 2017 at 8:11
  • \$\begingroup\$ Another option is in different color depths of RAW (8bit per channel) and JPEG files. \$\endgroup\$
    – Crowley
    Commented Jun 14, 2017 at 9:00
  • \$\begingroup\$ i have noticed that i set iso at 800 and more, so might be at that time noise generating and affecting in my image. \$\endgroup\$
    – Parth
    Commented Jun 21, 2017 at 13:46

4 Answers 4


The way that JPEG works. Your going from an uncompressed format to a compressed format.

How JPEG Works

"Downsampling is simply the process of reducing the chroma values by some factor (and therefore is the first step in losing information). In the JPEG format, there are three accepted possibilities: no downsampling at all, dividing the chroma values horizontally by two, or dividing the chroma values both horizontally or vertically by two.

The next step is to split the downsampled pixels in the image into 8 x 8 blocks. Each colour component is split up separately, and each component sample goes through the same process in what follows. Note that on many occasions, the size of the image will not be a simple multiple of eight pixels in either direction. This can result in some pixel artefacts being created along the right and bottom sides of a JPEG picture.

The next step is fun, but puzzling. Each 8 x 8 block is converted into another matrix using a Discrete Cosine Transform (DCT). This transform, which is similar to a Fourier transform, analyses the frequencies of the original values along each row and column using a set of cosine waves oscillating at different frequencies and amplitudes. The reason for doing this is that the higher frequencies can be minimized or zeroed out since we do not perceive their loss as acutely as the more energetic lower frequencies.

This converted matrix is then quantised. This is the main lossy part of the algorithm and the stage where we minimise the higher frequencies over the lower frequencies. One major result of this quantisation is that many higher DCT coefficients are zeroed out, making them extremely compressible in the next step.

The quantisation is accomplished by a set of 8 x 8 matrices, each one representing a different 'quality factor' for the JPEG image. Each cell is divided by the corresponding cell in the quantisation matrix and the result rounded (another lossy operation). Note that this does not involve matrix multiplication in the mathematical sense of the phrase.

Finally, the resulting quantised matrix is encoded using Huffman compression. To make the most use of the way the values in the matrix seem to radiate out from the top-left corner, the values are encoded not across each row for all rows but in a zig-zag pattern. This means that the zero cells tend to appear at the end of the zig-zag chain and therefore can be ruthlessly compressed (in fact, there's a special code that indicates that all remaining cell values are zero in the 8 x 8 block)."



A typical reason would be if you modify settings, like Saturation - either directly or via presets - it makes existing noise more prominent, easily to an unacceptable level.

To counter that, you need to use for example the Color Noise slider, or reduce Saturation back down.

  • \$\begingroup\$ yes, something like that, when i increase clarity or saturation its creating color noise, but if we see normal raw it is not visible as in jpeg, even i have doubt with photoshop, which is showing some more noise than actual. do you know which RGB to be used ? 8bit or 16bit ? \$\endgroup\$
    – Parth
    Commented Jun 15, 2017 at 5:47

There are several things that can increase perceived noise in a photo:

  • Increasing brightness/exposure in post processing. When you amplify the shadows you also amplify the noise in the shadows.
  • Increasing saturation. The will particularly affect chrominance noise.
  • Applying peripheral illumination lens correction. If you use lens correction to brighten up the corners of a photo that has light falloff in the corners you are raising the brightness levels of the corners. The noise in those darker corners will also be raised.

When i click image at that time Raw format doesn't contain any noise

As you describe your workflow it seems what may be happening is when you select the image you are viewing the jpeg preview generated by the camera and attached to the raw file. Many raw processing applications use the attached preview jpeg to display thumbnails of raw image files. Depending on your Photoshop settings, you can also see the jpeg preview image in certain modules within photoshop. The jpeg preview image probably had an amount of noise reduction applied by the camera.

but when i opened into Adobe Photoshop CC 2017 version and after modifying raw data and open to ps and save as jpeg gives colors noise.

When you start editing in Photoshop most of the in -camera settings applied to the jpeg preview are ignored. Ps opens your raw image and applies its default profile instead. If your default profile in Ps does not include any noise reduction and you don't add any while editing then none is being applied to the image as you edit and export it. Even if you do apply some noise reduction, if it is less than what the camera applied to the jpeg preview, then your edited image will be noisier than the jpeg preview you saw when you selected the image.

For more, please see:
Why do RAW images look worse than JPEGs in editing programs?
Why do RAW images in Darktable have a lot of noise?
While shooting in RAW, do you have to post-process it to make the picture look good?
Why is there a loss of quality from camera to computer screen
Why do my images look different on my camera than when imported to my laptop?
How can I undo Canon Auto Lighting Optimizer in Lightroom? Although the question is different, this answer directly explains what you are experiencing.

  • \$\begingroup\$ thanks @Michael Clark , is there any way to convert to jpg with minimum noise and max. post process on raw image? \$\endgroup\$
    – Parth
    Commented Jun 15, 2017 at 9:59
  • \$\begingroup\$ The more you comment the more it seems you may be calling jpeg compression 'noise'. Without examples in the question it is hard to answer, because you may not be talking about actual noise. \$\endgroup\$
    – Michael C
    Commented Jun 15, 2017 at 19:23

Actually you should try the best settings in Photoshop. Moreover as said above, there may be noise in RAW format.


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