I too have encountered this and didn't find it to suffer from mold. I would
give it a clean as described by Richard before preservation would commence.

Cheers
Marie

On Tue, 8 Nov 2022, 5:16 pm Shai Drori, <[log in to unmask]> wrote:

> IIRC this is a known issue with GX tapes.  It’s a breakdown of the
> formulation.  The EE variant suffers the most from this.  On the other
> hand, their LX tapes which are the most basic tapes hold up well.
>
> On Tue, 8 Nov 2022 at 5:12 Dust Mahrt <[log in to unmask]> wrote:
>
> > As time continues… Quality worsens. The analogue to the digital proves
> > that! Before that; reel to album.
> >
> > Peace,
> >
> > Dust
> >
> > PS
> > "It's gonna get worse"… Subhumans (UK)
> >
> > Get Outlook for iOS<https://aka.ms/o0ukef>
> > ________________________________
> > From: Association for Recorded Sound Discussion List <
> > [log in to unmask]> on behalf of Tim Gillett <
> > [log in to unmask]>
> > Sent: Monday, November 7, 2022 7:21:49 PM
> > To: [log in to unmask] <[log in to unmask]>
> > Subject: Re: [ARSCLIST] filmy/powdery substance on open reel tape
> >
> > I noticed this in the late 90's with the same TDK GX tapes recorded
> > new in the late 80's.
> >
> > As you say more of a powdery film. I never did any proper testing but
> > recall it didnt seem to induce an audible spacing loss then. Even so
> > whenever I played them I regularly cleaned the powder from the tape
> > path just to be sure. I still have some of these recorded tapes but
> > havent checked them for many years  Maybe these days the problem is
> > worse now though?  On yours have you noticed muffled playback after a
> > time?
> >
> > Tim Gillett
> >
> > Perth,
> > Western Australia
> >
> > ----- Original Message -----
> > From: "Association for Recorded Sound Discussion List"
> > <[log in to unmask]>
> > To:<[log in to unmask]>
> > Cc:
> > Sent:Mon, 7 Nov 2022 15:01:13 -0500
> > Subject:[ARSCLIST] filmy/powdery substance on open reel tape
> >
> >  Wondering if any of you can help me identify a white filmy/powdery
> >  substance on the pack of an open reel tape. At first glance it looks
> > like
> >  mold but on closer inspection it isn't. There is some kind of
> > chemical
> >  breakdown happening obviously and the tape is polyester with
> >  back treatment. The tape is TDK GX 35/180Bm. There are other tapes in
> > the
> >  same collection with the same condition but not sure of the brands as
> > they
> >  are in generic boxes. The only thing in common is that they all are
> > back
> >  coated.
> >
> >  Any information on what this is and how to get rid of it will
> >  be appreciated.
> >
> >  --
> >  Jonathan
> >
> > -------------------------
> > Email sent using Optus Webmail
> >
> --
>
> Cheers
> Shai Drori
> Expert digitization services for Audio Video
> 3K scanning for film 8mm-35mm
> Timeless Recordings Music Label
> www.audiovideofilm.com
> [log in to unmask]
>