Is this oxidization or something else?

[LookCloser]

Hi All,

 

I've taken a look at my Kolari UV bandpass filter today and noticed some discolouration. Shown at the top perimeter of the filter in the attached image.

I am wondering whether this is normal oxidization, user error or manufacturing issue?

 

The discolouration is visible from the rear (lens side) of the filter but not the front and it looks like it is below the rear surface of the filter.  i.e. under a laminated layer.

 

I am happy to take responsibility if it is user error, I just need some information on what actually is going on here.  To me it looks like delaminating layers.

 

 

Please excuse the dust .

 

Mat

 

 

[colinbm]

Yes you have a problem with this filter, it needs to be replaced by Kolari, good luck with that & I hope you have some proof of purchase, either paper or electronic.

[Andy Perrin]

I agree it is delaminating. They should replace it. That’s not user error.  

[Andrea B.]

I have a filter (not the KYU) where a small delamination happened around the perimeter, probably due to uneven or incomplete or dried out cement, but it does not affect the photo outcome. That area does look larger than the one I have, so I also think you should contact Kolari about this.

 

Have you noticed any discolored areas or blurred areas in your photo?

 

Any oxidation or other type of surface corrosion is easily seen to be on an outer surface of the filter, not between cemented layers. Such corrosion is also easily felt as either a kind of crusty deposit or greasy deposit.

[LookCloser]

Thanks Colin, Andy and Andrea,
I have proof of purchase and will send Kolari an email.

Andrea, I took a few images as soon as I noticed it and can't notice any distortions or cloudiness so I think it is still performing it's function for now.

Thanks all for your advice.
Mat

[Andy Perrin]

Yeah, I think the operative words are “for now.” Delamination is probably going to get worse. It is kind of amazing how messed up a filter/lens can be and still work, though!

[JMC]

Not defending filter manufacturers here, but these types of effects are not unusual on coated filters. I have some Thorlabs UV bandpass filters, and they have developed issues like this around the edges within a couple of years of purchase. I'm not sure what the specific mechanisms involved here are, but for instance UG filters will have issues with surface degradation over time. When uncoated we can try and clean them and remove the issue for a while, but it is likely to come back. If a glass like that is then coated, degradation at the surface of the glass will be underneath the coating layer and cannot be cleaned. This can and does impact the adhesion of the coating. While the coating may slow things like this down it is unlikely to completely eliminate the problem. I have some old Zeiss metal interference filters which have pretty much disintegrated, while others which are a similar age are still usable.

[Andy Perrin]

I guess the question is how old this filter is? I mean, it’s definitely not right in a brand new filter or one only a year old. Surely that would come under quality assurance issues, even if such problems are common to these types of filter. I have never seen this with any filter I own, including my many Thorlabs filters. 
 

I do wonder if a key element isn’t humidity here. Certain members have mentioned that their filters degraded rapidly in a humid climate. I air-condition my apartment and keep the humidity around 20-50% year round. 

[JMC]

1 hour ago, Andy Perrin said:

I guess the question is how old this filter is? I mean, it’s definitely not right in a brand new filter or one only a year old. Surely that would come under quality assurance issues, even if such problems are common to these types of filter. I have never seen this with any filter I own, including my many Thorlabs filters. 
 

I do wonder if a key element isn’t humidity here. Certain members have mentioned that their filters degraded rapidly in a humid climate. I air-condition my apartment and keep the humidity around 20-50% year round. 

Andy, I absolutely think humidity is a contributing factor to these effects.

[LookCloser]

In answer to the above queries, the filter is 18 months old and has been well looked after. I have had no issues with humidity in any of my other gear (with which it has been stored).  However, from now on I will be storing all my filters with Silica descant sachets.

[colinbm]

Silica descant sachets attract the moisture !

[Andy Perrin]

19 minutes ago, colinbm said:

Silica descant sachets attract the moisture !

 

Yep, which leaves the air around them drier, if that volume of air is isolated from the rest of the room. That is how they function and why they are popular in electronics packaging with the familiar “Do Not Eat!” admonition for those who are inclined to stick unfamiliar objects in their mouth. 

[colinbm]

2 hours ago, Andy Perrin said:

 

Yep, which leaves the air around them drier, if that volume of air is isolated from the rest of the room. That is how they function and why they are popular in electronics packaging with the familiar “Do Not Eat!” admonition for those who are inclined to stick unfamiliar objects in their mouth. 

You need to read up on what Ulf & I have found.....

[ulf]

1 hour ago, colinbm said:

You need to read up on what Ulf & I have found.....

I think Andy's answer is quite correct and do not remember me claiming anything else:

https://en.wikipedia.org/wiki/Silica_gel

Sometimes I too do as LookCloser, storing my filters in closed containers with descant material.

However most of the time the humidity indoors is rather low here.

[GaryR]

Southern Ontario humidity can be extremely high during the summer months. I think I'll refrain from shooting outdoors with the Kolari UV, until the current humidity drops.

[LookCloser]

I just needed to follow up on this post.

I contacted Kolari regarding this filter, providing the image above and my proof of purchase.
I am pleased to say that their customer service was fantastic!

I was told that there was no need to return the faulty filter and that they would send out a new one immediately, which I received today
I did have to cover the cost of postage for the new filter, but since I did not have to pay postage to return the old one I thought that wasn't unreasonable.

Thank you Kolari, your customer service was great.

[colinbm]

That is great, that is two happy customers that Kolari have made.

[Andy Perrin]

I’m glad they fixed it.