[couliseaux]

I bought a used Katzeye and it's ridiculously awesome. I love it. It had a few dust spots on it and I tried to clean it twice, only to make it worse each time. I used a brush and a can of dust remover. can i use lens cleaner and a cloth? it seems daunting. please advise.

[JohnBee]

There are to ways to clean a focusing screen.
The first method is the easiest... use a dust blower.
However, this doesn't address smudges and marks that will eventually build-up on the screen. So... that leaves you with option two.

Option two is to wash the screen since you can't effectively wipe the screen(given it's design) the only "effective" way I've found to get a screen back to it's like new condition is to wash it in dish soap. The entire affair can be done quite easily, though it will require a measure of care on your part to make sure that the screen doesn't fall in the process because you will also be blowing the water off of it afterward with a blow-dryer(to be careful).

Here's my method:

1. get three clean foam cups, a bottle of distilled water, some dish soap(sensitivite skin ver), a roll of toilet paper(hehe) and a hair-dryer.

2. Drop three drop of soap in the first cup and fill it with distilled water.
3. Fill the remaining two cups with clean distilled water.
4. taking your plastic screen tweezers, grab your screen and soak it in the water for a good 30mins. This will allow the soap to break down the oils and residue that have built-up on on your screen.
5. Once it has soaked, you can carefully swish it around in the solution to help propagate the cleaning agent throughout the fine groves of the fresnel texture. Don't worry if the screen falls into the cup, the foam is not hard enough to affect the screen. Though fishing it could require care.
6. Carefully lifting the screen out of the water allow to drip dry and dip it in the first clear water rinse. Rinse and repeat until the screen shows no more signs of cleanser(soap colors) and shows rapid clear dissipation. However... do not allow it to dry out the air(it will leave residue stains).

Now here comes the hard part...

7. With the hair-dryer in one hand and your screen in the other. gently place the screen above the tissue roll so that the corner of it is gently resting on the face while blow drying the screen along the edges(not face on!). This will force the water droplets off the screen and into the tissue quickly enough to dry without leaving residue marks.

I've been doing my own Katzeye screens this way once per year without any problems. Though I am always very careful so that the blow-dryer doesn't blow the screen off the tweezers(its very risky imo), BUT... its the only way I've found to make the screens look like new again.

Hope this helps.

[Nass]

^^ awesome JohnBee, thanks for sharing

[couliseaux]

I ended up just winging it and using a lens cloth with liquid cleaner. No gloves or tweezers. I got it out with a pen cap. It worked, with all the dust removed sans a brown speck right on the knurled circlie thing. it was a dumb thing to do and I'm lucky I didn't ruin it or the mirror– but at two AM and your sick of worrying about it, you do stupid things and get lucky.

[KxBlaze]

I did the same thing in making my screen worse when trying to clean a few dust spots. So now my rule of thumb is if it does not affect your picture you are better off leaving it be. Besides getting more dust on the screen you can easily scratch it. Removing 1-2 pieces of dust is not worth the risk of scratching (especially a screen that is worth more then $120).

[Lowell Goudge]

There are to ways to clean a focusing screen.
The first method is the easiest... use a dust blower.
However, this doesn't address smudges and marks that will eventually build-up on the screen. So... that leaves you with option two.

Option two is to wash the screen since you can't effectively wipe the screen(given it's design) the only "effective" way I've found to get a screen back to it's like new condition is to wash it in dish soap. The entire affair can be done quite easily, though it will require a measure of care on your part to make sure that the screen doesn't fall in the process because you will also be blowing the water off of it afterward with a blow-dryer(to be careful).

Here's my method:

1. get three clean foam cups, a bottle of distilled water, some dish soap(sensitivite skin ver), a roll of toilet paper(hehe) and a hair-dryer.

2. Drop three drop of soap in the first cup and fill it with distilled water.
3. Fill the remaining two cups with clean distilled water.
4. taking your plastic screen tweezers, grab your screen and soak it in the water for a good 30mins. This will allow the soap to break down the oils and residue that have built-up on on your screen.
5. Once it has soaked, you can carefully swish it around in the solution to help propagate the cleaning agent throughout the fine groves of the fresnel texture. Don't worry if the screen falls into the cup, the foam is not hard enough to affect the screen. Though fishing it could require care.
6. Carefully lifting the screen out of the water allow to drip dry and dip it in the first clear water rinse. Rinse and repeat until the screen shows no more signs of cleanser(soap colors) and shows rapid clear dissipation. However... do not allow it to dry out the air(it will leave residue stains).

Now here comes the hard part...

7. With the hair-dryer in one hand and your screen in the other. gently place the screen above the tissue roll so that the corner of it is gently resting on the face while blow drying the screen along the edges(not face on!). This will force the water droplets off the screen and into the tissue quickly enough to dry without leaving residue marks.

I've been doing my own Katzeye screens this way once per year without any problems. Though I am always very careful so that the blow-dryer doesn't blow the screen off the tweezers(its very risky imo), BUT... its the only way I've found to make the screens look like new again.

Hope this helps.

I would simply add one change to this.

You may wish to consider not using distilled water but but add a small portion of film rinsing agent. This is actually a very mild soap that is designed for modifying the surface tension of the rince water so that it will not form droplets. The formation of droplets, regardless of size will ultimately lead to a spot because no matter how hard you try, you will never end up with pure water. There will always be some disolved minerals in the water, even if it is carried over from the first rinse bath. The ring that these spots leave is due to the concentration of minerals as the droplet evaporates, but if you use a solution that is specifically designed NOT to permit this, the problem is avoided. The film rinsing agent is intended to achieve this and avoid spotting on the negatives. If it can result in clean negatives, it can result also in a clean focusing screen

[JohnBee]

I would simply add one change to this.

You may wish to consider not using distilled water but but add a small portion of film rinsing agent. This is actually a very mild soap that is designed for modifying the surface tension of the rince water so that it will not form droplets. The formation of droplets, regardless of size will ultimately lead to a spot because no matter how hard you try, you will never end up with pure water. There will always be some disolved minerals in the water, even if it is carried over from the first rinse bath. The ring that these spots leave is due to the concentration of minerals as the droplet evaporates, but if you use a solution that is specifically designed NOT to permit this, the problem is avoided. The film rinsing agent is intended to achieve this and avoid spotting on the negatives. If it can result in clean negatives, it can result also in a clean focusing screen

That definitely sounds interesting and I'd certainly like to give it a try. The omission of a hair drier would certainly simplify the cleaning process a great deal. Though I'm not sure if this will always be feasible to people at home. . Having said that, I wonder if they're alternate solutions to accomplishing a similar effect using common household products?