I doubt that the cd's were not flat to begin with. I have cd's from the 
same batch that I stored in total darkness and they perform flawlessly.
Shai

On 3/1/2010 12:40 PM, Jos Van Dyck wrote:
> Shai Drori wrote:
>
>    
>> The servo system of the cd is very robust. It is built to cope with
>> physical deviations.
>> What you are describing is exactly what I am experiencing.
>>      
> Could it be that the CD-Rs were not 100% flat from the start, hence poorly
> written to the outside?
>
>
>    
>> Can you give me more info on how the cd was stored?
>>      
> The CD-Rs are stored vertically in dedicated cupboards, in a conditioned
> archive room with constant temperature and humidity, no light.
>
> Jos
>
>