Why are there some films are occasionally fade and /or yellow in colour?
After a film is exposed, a latent image is formed in the emulsion. If the film is left too
long too be processed, the latent image could fade out. If the film has been exposed to
heat as well, the dye in some layers of the emulsion could also be damaged. Damaged dyes
could cause yellow, yellowish green, or purplish colour.
Is it certain type of film could resist changes in colour better than other type?
Yes. Certain type of film depending on the emulsion design and the silver contents could
have better resistance to time and heat damages. Some professional films are easier to
change colour because they do not use preservative as in amateur film. Preservative can
cause unfaithful reproduction of colour.
Should I process my film as soon as it is exposed?
Yes, certainly. Prolonged delay could reduce contrast and cause fade colour.
Why is it I get more yellowish film in summer?
Customer left their cameras in the car on a hot summer day could damaged the film in few
Why is it I get more faded film in winter?
It is because customer can not finish the film in a short while as it is in summer. Many
customers took only a few pictures during Christmas and do not have a chance to finish the
film until spring.
Whenever I print pictures with lots of red colour on them, such as people wearing red
dresses, people standing on red background, red cars, I always get blue face on them, why?
It is because your computer has seen too much green colour (green and magenta are opposite
colour) on your negative and has ordered a cutoff immediately. You can compensate the
colour by adding more magenta manually.
When I print people standing on grass, or on green background, why is it I get purple
face or purple colour road on them?
It is because you computer has seen too much magenta colour (green and magenta are
opposite colour) on your negative and has ordered a cutoff immediately. You can compensate
the colour by reducing magenta manually.
My colours are always in correct, could it be caused by my photographic chemistry?
In-correct colours are usually caused by in-correct colour balance adjustment. You should
check the calibration of you machine before checking the chemistry.
What colour should I use to calibrate my printer?
You should use only gray colour.
Why do I use gray colour?
18% reflection gray colour was determined to be the average print density of most
What is a control negative?
A control negative is a picture containing mainly gray colour to be used on calibration of
printer on the specified type of film.
Can I make my own control negative?
Yes. You can use a well-controlled light source to photograph a gray card.
What is ring around tests?
Ring around tests are a set of setup procedures to calibrate a printer to a correct colour
balance. It is a method of printing many prints on different colour settings such that you
can determine the best colour balance to be used on a particular type of film.
If I have very precision colour balance adjusted, would I get precision colour on every
Not necessary, every batch of film, paper has its own colour deviation.
Why is it my white colour is not white?
You may have stain on your paper chemistry.
What caused stain on prints?
Stain can be caused by old chemistry, or new chemistry not properly mixed.
Is it certain make of paper can resist stain better than other make?
Yes. Certain make of paper can resist over developing and or get stain resistance better
than other make.
Is my stain level changing with my volume of business?
Yes. The more business you have, the less stain you will get. Stain normally is higher
after a long period of close down of your machine, such as Monday morning. It can be
reduced after a period of operation.
Is the quality of colour determined by my photographic chemistry?
No. The film or paper determines the quality of colour. Photographic chemistry (Except
Kodakchrome chemistry) does not contain dyes. However, photographic chemistry affects the
condition of formation of colours. Therefore, many people mistakenly believe the colour is
given by the chemistry.
If you are right, why is it my chemistry does affect my colour?
Photographic chemistry affects colour if your chemistry off specifications.
What makes my chemistry off specifications?
Improper mixing of chemistry, low replenishing, low utilization, low turn over rate can
put your chemistry off processing limit. In a more simple word, if you do not have enough
business to turn over your old chemistry, you are in trouble.
If I do not have enough business to keep my chemistry fresh, then what can I do?
Most manufacturers will tell you to dispose the old chemistry. Hi-Tech will tell you to
maintain your old chemistry.
What does maintaining my chemistry mean?
Simple philosophy, prevent your chemistry from turning bad. Prevention is better than
I have very good business, should I maintain my chemistry?
You should monitor your chemistry. Over replenishing could cause over developing, and
resulting high contrast.
How do I know my chemistry off limit?
You can use control strip to monitor your chemistry, or simply by experience.
Is control strip reliable?
Control strip is a pre-exposed film or paper in the factory under tight specified
conditions. It is reliable only when it is fresh.
Why is it my control strip always tells my chemistry is bad even though I have good
Your control strip is outdated, or improperly kept.
Can I tell the conditions of my chemistry simply by using my eyes?
Yes, provided you have experience. Hi-Tech can help you to get such experience.
Is it true that certain brand of film or paper would produce better colour by using
their own brand of chemistry?
No. Modern photographic chemistries are generally designed under several processing
specifications, such as C41, C41B, C41RA, RA4, E6, etc. As long as your chemistry meets
the specification as required, they will be equally good.
If I switch over from one make of chemistry to another make, would it affect my colour?
No. Colour dye is not in the chemistry. They are in the film or paper.
Why is it my manufacturer tells me different from what you said?
Most manufacturers will like to keep you in the dark. They do not want you to know too