I'm facing one thing that is very frustrating. Every time that I upload long exposure images to either photoshop or lightroom, they get blue and red specs,and when I export them (no matter which format) they get worse. I've had looked up for some solutions in photoshop like increasing the cache levels to maximum (8), the tile cache, but nothing.

This image was shot with a Nikon d7100, 30s, ISO 1000

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  • I don't see any red specks, and the blue 'specks' look like young (hot) stars. It is possible that you are picking up 'hot' pixels with long exposures. Normally, you won't notice them. Try taking a long exposure with the lens cap on. – Mick Oct 25 '16 at 9:57
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    What camera? Are you using any form of dark frame subtraction? ISO and shutter length? – Michael C Oct 25 '16 at 10:04
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    At what point do your images not have those blue and red specs? You are making a comparison here, without starting what you comparing. – null Oct 25 '16 at 10:30
  • Are you taking about Mobile versions? Because one does not Upload to Lightroom, one Imports and then Exports. – Itai Oct 25 '16 at 20:36
  • these magical blue and red specks are called...stars – osullic Oct 25 '16 at 22:23

The question is likely not being well received as it implies the noise is coming from the upload, and it is not, it is coming from either long exposure noise (a statistical noise pattern from sources such as thermal noise in the sensor) or from high ISO noise (basically from pushing the sensor near its limits where the amplification, especially if digital, is amplifying the noise from the sensor), or both.

There are a number of things you can do to address this. First, shoot raw, so you can preserve all the data present from the sensor. Secondly, if your camera supports it, turn on Long Exposure Noise Reduction, and if not consider doing it by hand. Long Exposure Noise Reduction involves taking two exposures, one with light from the sky, and one with the shutter closed and/or lens covered so all that is present in the image is the noise. You then subtract the latter from the former (or the camera does for you) as a way of removing some level of noise from the image (since the noise is by its nature random this cannot remove it all, but it removes areas that may be statistically repeatable, e.g. if portions of your sensor have more noise than others that result in a bit of a glow in one area, it can almost entirely remove such a pattern. Cameras that do Long Exposure Noise Reduction automatically actually affect the raw image by doing both exposures in-camera (taking twice as long for the image); it is one of the few image settings that actually get baked into raw data. Doing it outside is relatively easy, you take two images and do it in post processing with layers in photoshop (you cannot do it in Lightroom manually) - search for "Dark Frame" in astrophotography postings.

As you convert the image in Lightroom or ACR (which comes before photoshop for raw images) you can remove more of the noise with noise reduction, but at the expense of detail. This removal is a calculated removal, and so if over-used will reduce the quality of the image. Depending on your lightroom/PS defaults, yours may be set to low now, try increasing it and watching (zoomed 100%) until you see the tradeoff you like between noise reduction and star detail. You can also reduce the visibility of it by adjusting black point, contrast, and in the newer PS and LR the 'dehaze'. Experiment to see which give you the best result, as this is quite subjective - some people are more tolerant of noise than others.

Noise, and astro-photography noise, is widely discussed in postings; spend a bit of time reading about it and you may be able to ask more specific questions.

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