[Photoshop] How to save PNG images with bit depth of 32bit, 48bit, 64bit

I got you

2020.08.15 (Sat), When I took a look at the PNG image rendered with Blender (freestyle, 3840×2160, RGB, color depth 16bit, compression rate 100%), it was quite large, exceeding 5MB.

When I [right-clicked] those .PNGs and looked at [Properties] → [Details], I found that the bit depth was 64 bits.

Even in the best BB material I’ve seen, most bit depths were 32 bits.

I thought I could do this with Photoshop, which I always use, so I looked into how to convert PNG to 64bit, but I couldn’t find any information.

So, when I saved and exported the image as a sample PNG in Photoshop,

I succeeded in saving PNG images at bit depths of 64bit and 48bit.

By doing this, you will be one step closer to generating high-resolution PNG images.

This time, I will show you how to save PNG images with 32-bit, 48-bit, and 64-bit bit depth in Adobe Photoshop.

PNG bit depth

Save as PNG color depth 32bit

• Canvas size: 100x100px
• Screen resolution: 72dpi

1. Create a new canvas or open an image.
2. Select Image → Mode → [32ビットチャンネル].

2. [Export] → [Quick export as PNG[PNGとしてクイック書き出し]] or [Export format…]

2.1 [Quick export as PNG][PNGとしてクイック書き出し] → [Save as].

2.2 [Export format…] [Export] → [Save] as is.

Saving is now complete.

3. Right-click on the .png → [Properties] → [Details] → Check [Bit Depth].

Bit depth 32bit PNG click export	Bit depth 32bit Export format…

Save as PNG color depth 48bit

• Canvas size: 100x100px
• Screen resolution: 72dpi

1. Select [Image] → [Mode (M)] → [16bit/Channel (N)][16bit/チャンネル(N)].

1.1 Nothing special when changing from [8bit][8bit] to [16bit][16bit]

1.2 When changing from [32bit][32bit] to [16bit][16bit]

Reducing the bitness of your document will affect the appearance of your HDR layered images. Combine layers before changing bit depth?

I want to maintain a clean state when reducing the number of bits, so I use [Merge].

[HDRトーン]

[HDRトーン]If you set it as follows, it doesn’t seem to be much different from 32bit.

• Preset: [Custom]
• Method: [Exposure light and gamma]
  • Exposure light (X) [0 .00]
  • Gamma (G) [1 .00]

2. [File (F)] → [Save As (A)…]

3. Change [Save as type] [Photoshop(.PSD,.PDD,.PSDT)] to [PNG(.PNG,*.PNG)] and then [Save].

Saving is now complete.

4. Right-click on the .png → [Properties] → [Details] → Check [Bit Depth].

Bit depth 48bit Save as

Save as PNG color depth 64bit

This is the method I found this time.
It is possible that there is a setting that requires saving in 64 bit.

*Caution: This will place a load on your computer.

1. Select [Image] → [Mode] → [16bit/channel][16bit/チャンネル].
2. Please increase the canvas size and screen resolution as much as possible.

Setting Example

• Canvas size: 4000×2000 px
• Screen resolution: 300dpi

3. Keep your images complex.

Success

• Many layers (3 or more)
• Multicolor system

If you do not clear the following, you will fail quite a lot.

Failure

• Less layers
• Monochromatic

4. [File (F)] → [Save As (A)…]

I think it’s easier to succeed if it takes longer than normal storage.

5. Right-click on the .png → [Properties] → [Details] → Check [Bit Depth].

Bit depth 64bit Save as

When the bit depth becomes 64bit class, the file size becomes more than MB.

16-bit multiple documents are marked with a #

However, this is not necessarily the case as it was possible to output PNG in 64bit even with RGB/16.

I think 32 bit is basically fine.

• Illustration/Game: 32bit
• Web：8bit

With this method, it takes a lot of effort to save in higher than 32 bits.
I don’t think it’s okay to be that nervous.
If you are particular about it, it is better to use other image formats for higher quality.
dds,tga,tiff etc.

Reference

Color depth – Wikipedia

Operating Environment

• Windows 10 Pro
• Adobe Photoshop CC 2020