Why isn't one image white and the other black according to my code

 a=ones(78);
>> b=255*ones(78);
>> figure,imshow(a);
>> figure,imshow(b);
>>

If I run the above code then one image should be bright while the other dark(I am using uint8 thus range is 0-255) but the fact is both turn out to be white. May I know why ?

Answer 1

[Ben11]

You don't cast anything as being uint8. Try:

figure, imshow(uint8(a));

then it will be black