# Shade , Tint, satMod percent values

• ### Question

• Hi All,

How to calculate values for <a:tint> and <a:shade>. Not finding any proper formula.

what is shade %? Is it 25?

If yes,
what is shade %? Is it 250?

Any standard formula to get %?

• Edited by Thursday, November 10, 2011 10:04 AM
Thursday, November 10, 2011 10:03 AM

### All replies

• Hi NacyDrew,

Would you please tell me where this tag will be use, Excel, Word or PowerPoint?

Have a good day,

Ice

Friday, November 11, 2011 2:29 AM
• It will be used in powerpoint.

Friday, November 11, 2011 10:37 AM
• Also,

The concluded method of applying tints or shades is:

1. Convert hex to rgb

2. rgb to srgb (by dividing by 255)

3. srgb to linear rgb  using the algo from thread

4. Apply tints or shades as:

·         *Or* Tint each component using these formulas where Tint is a value from 0-1:

=IF(Tint>0,Red*(1-Tint)+Tint,Red*(1+Tint))

=IF(Tint>0,Green*(1-Tint)+Tint,Green*(1+Tint))

=IF(Tint>0,Blue*(1-Tint)+Tint,Blue*(1+Tint))

5. Convert linear rgb to srgb by algo from above thread

6. Convert srgb back to rgb ( val*255)

7. back to hex

But,

For hex = #FF99FF with <a:shade val="25000" > i.e 0.25

Output produced is #884F88 by my way

where as per office it should produce #895089

(though these two are very similar)

Is this process correct ?

If am missing anything please let me know the right way.

Thanks

• Edited by Friday, November 11, 2011 12:21 PM
Friday, November 11, 2011 10:43 AM
• I think your must have some rounding errors.

Red = 0xFF
divide by 255 = 1
the algorithm function returns: 1
the second algorithm returns 0.537098730483194
multiply by 255: 136.960176273214
round to 137
in hex: 89

Green = 0x99
divide by 255 = 0.6
algorithm gives 0.318546778125092
algorithm gives 0.31260632082132
times 255 gives 79.7146118094366
round to 80
in hex 50

Blue same as red gives #895089

Enjoy,
Tony
www.WordArticles.com
• Marked as answer by Thursday, November 17, 2011 9:38 AM
• Unmarked as answer by Thursday, November 17, 2011 9:53 AM
Wednesday, November 16, 2011 7:54 PM
• Thanks tony values helped to solve the problem
Thursday, November 17, 2011 9:38 AM
• But what if shade or tint % is above 100?
Thursday, November 17, 2011 9:53 AM
• But what if shade or tint % is above 100?

It can't be - it would violate the schema and PowerPoint wouldn't open the file.

Enjoy,
Tony
www.WordArticles.com
Friday, November 18, 2011 8:38 AM