为互联网保存图像

Krita 的默认保存格式是 *.kra 格式。此格式可以保存 Krita 能够对图像进行的一切操作：包括图层、滤镜、辅助尺、蒙版、色彩空间等。为了保存这么多的数据， *.kra 文件的体积一般都很大，对于上传到互联网来说很不方便。如果人们只能使用 *.kra 文件来查看图片，他们的流量肯定两下就用光了。因此我们需要为互联网用途优化输出的图像。

这涉及到下面几步：

  1. 先把图像保存为一个 .kra 文件，这是你的工作文件，同时也作为应对操作失误的备份。

  2. Flatten all layers. This turns all your layers into a single one. Just go to Layer ‣ Flatten Image or press the Ctrl + Shift + E shortcut. Flattening can take a while, so if you have a big image, don’t be scared if Krita freezes for a few seconds. It’ll become responsive soon enough.

  3. Convert the color space to 8bit sRGB (if it isn’t yet). This is important to lower the filesize, and PNG for example can’t take higher than 16bit. Image ‣ Convert Image Color Space… and set the options to RGB, 8bit and sRGB-elle-v2-srgbtrc.icc respectively. If you are coming from a linear space, uncheck little CMS optimisations

  4. Resize! Go to Image ‣ Scale Image To New Size… or use the Ctrl + Alt + I shortcut. This calls up the resize menu. A good rule of thumb for resizing is that you try to get both sizes to be less than 1200 pixels. (This being the size of HD formats). You can easily get there by setting the Resolution under Print Size to 72 dots per inch. Then press OK to have everything resized.

  5. Sharpen the image a little. This is especially necessary for social media. Social media websites often scale and convert your image in such a way that it gets a little blurry, because they optimize towards photos and not paintings. To have your images stay sharp, it is worth it to run a sharpen filter beforehand. Because the sharpen filter is quite powerful, you are best off adding a sharpen filter mask on top of the stack and lowering its opacity till you feel the sharpness is appropriate.

  6. 把图像另存为对网络安全的格式。有三种较好的选择：

JPG

如果图像有大量不同的色彩，如传统绘画等，可选用此格式。

PNG

如果图像色彩不是特别丰富，如漫画那样的黑白或者像素图，可选用此格式。选中 尝试保存为索引 PNG 可进一步优化图像大小。

GIF

仅用于动画 (今年将实现支持)，或颜色种类特别少的图像，因为这是一个索引图像格式。

保留图像透明度

../_images/Save_with_transparency.png

Saving with transparency is only possible with GIF and PNG. First, make sure you see the transparency checkers (this can be done by simply hiding the bottom layers, changing the projection color in Image ‣ Image Background Color and Transparency…, or by using Filters ‣ Colors ‣ Color to Alpha…). Then, save as PNG and tick Store alpha channel (transparency)

点击保存，然后就可以把输出的图像上传并分享了！