Proper Way To View Api Ammonia Test

[Kaidonni]

Quick question - what is the proper way to view the liquid API ammonia test? I know daylight trumps any artifical lighting, but should the test tube be held flat against the card or slightly above it? These both give different effects: flat against the card and it's vivid yellow; slightly above the card and it's somewhere between 0 and 0.25ppm as far as my eyes can determine.

Thanks.

 

[TwoTankAmin]

Hold it against the card right next to the colored bars. Have whatever light you are using come from behind you so it shines evenly on the test tube and the bars.
 

 
6. Read the test results by matching
the test solution against the
Ammonia Test Color Chart. The
tube should be viewed against
the white area beside the color
chart. Color comparisons
are best made in a well-lit area.

From the API test instructions.
 
Have a look at the pics in this thread http/www.fishforums.net/index.php?/topic/435022-api-master-test-photos-what-are-my-readings-im-a-bit-colourblind/

 

[eaglesaquarium]

To add to this.... natural light is also best, whenever possible.

 

[Kaidonni]

Thank you for the replies. I now only use natural light, except for certain instances with specific tests (such as Nutrafin pH, and only under certain artificial lights that I know give very similar readings to what I see in daylight).