README update

Former-commit-id: 79ea4bbfe747c18b4401e037aa350c23a9dc7fa2
Former-commit-id: 4feab90a769c9a8a52acc3a0b7223813c193756a

README.md

@@ -39,10 +39,20 @@ Note: Right-to-left languages (arabic, hebrew, etc.) are not supported.
 
 ### Contributing artworks ###
 
-* RGB we mean is always sRGB, _pure white_ we say is always D65 (6 500 K). If you have a monitor calibration device, this is our desired target.
-* Master material for picture (e.g. psd) can be either RGB/8 or Lab/16.
-* To comply with the game's art style, only the 12-bit colours must be used (each channel: 0x00, 0x11, 0x22 .. 0xEE, 0xFF), though there is some exception.
-* Every final audio must be in OGG/Vorbis, q 10.
+* RGB we mean is always sRGB, _pure white_ we say is always D65 (6 500 K daylight). If you have a monitor calibration device, this is our desired target. (calibration software must be _DisplayCal 3_)
+* Master file for the picture (e.g. psd) can be either RGB/8 or Lab/16.
+* Every exported audio must be in OGG/Vorbis, with quality ```10```.
+* When exporting the image, if the image contains semitransparent colours, export it as TGA; if not, export it as PNG.
+
+        Instruction for exporting the image as TGA
+        
+        1. In Photoshop, File > Export > Quick Export as PNG
+        2. Save the PNG somewhere
+        3. Open up the PNG with Paint.NET/GIMP
+        4. Export the image as TGA
+        5. Include the converted PNG to the project
+
+
 
 
 ## Who do I talk to? ##
@@ -87,4 +97,4 @@ This game is proprietary (yet).
 
 개발 문서와 작업용 리소스(psd 등) 또한 이 저장소에 포함되어 있습니다. gcx와 numbers 형식으로 된 문서를 읽고 수정하기 위해 맥 컴퓨터가 필요할 수 있습니다.
 
-이 프로젝트에 대한 기여는 영어로 이루어져야 합니다. 따라서 코드나 주석 등을 작성할 때는 영어를 사용해 주십시오.
+이 프로젝트에 대한 기여는 영어로 이루어져야 합니다. 따라서 코드나 주석 등을 작성할 때는 영어를 사용해 주십시오.